While I honestly suggest checking out the far more indepth history lessons over at Sarna.net or grabbing the Battletech primers from the table top game here's the Battletech Universe history in a nut shell 
Up until about 1997 our two universes are fairly close together, shortly after the collapse of the USSR however things change as we see the Russian government over thrown, a new cold war start followed by the formation of the Western Alliance and generally a lot of civil war in Russia. In 2017 the first ship is sent to Mars, and a year later two scientists named Takayoshi Fuchida and Thomas Kearny begin publishing a bunch of works that basically says you can punch a hole in space and time, however they get made out to be nut jobs and laughed at. By 2020 we have fusion reactors and by 2086 when the Terran Alliance forms things are getting fairly busy in SOL but tensions are rising as we close out the 21st Century.
Into the 22nd those two nut jobs every one laughed at and who died in obscurity? Well two years into the new century they are proven right and a year later the Terran Alliance start the Deimos project to make their Hyper Space drive a reality the science community eats some humble pie and name it after the two people they abused and call it the Kearny-Fuchida drive installing it into a ship called the TAS Pathfinder it goes for a small hop to Tau Ceti and by 2110 Humanity has it's first outpost on the imaginatively named 'New Earth' problem is though that things are about to become really busy as people want well away from the over bearing dolts on earth so they start slapping jump engines on anything they can for the next 20 years... Until some one forgot to put the carbie on the Liberator right and it kinda just vanishes.. Leading the boys in charge to get a bit annoyed at the loss of life and make the Colonisation Procedure which basically says 'you have to have an escort from the new Terran Space Navy and a few other things', it doesn't really change much though people are all like screw you we want out and by the time the first Survey/Census to find out how many systems they can exploit, er I mean help grow in 2174 humanity's already on a hundred plus systems and growing but that leads to some Cartel's forming and this mad family named Liao's start to power they do some cleansing on earth and well have to leave in a hurry.
Anyway things continue to grow and groups start to form until about 2234 when a few of the colonies begin to get a little jack of the overbearing Terran Alliance constantly coming over drinking all the booze, eatting all the pizza, throwing parties and refusing to help pay the bill for the repairs after and Denebola decides 'screw this' and declares independence, thing is they aren't the only one's sick of it and rebellion leads to the war of independence the Terran Alliance is all we will crush you, only they are about as useful as a 4 Barrel Holly carb on a 3 cylinder engine and get sent home with their tails between their legs, in response the alliance throws a hissy fit around 2238 because the Liberals get into power back on Terra and throw the bath water out of the tub telling the colonies their all ungrateful sods and that if they don't want Terra to help them and even if they do too bad, they aren't getting any help no more. They then limit themselves to about 1 jump from earth (30 LY). This leads to a lot of resentment and not a few deaths because well not every colony is self supporting for a start but also sees the birth of what will be what are now in 3025 the great houses because they all need to kinda come together to stop themselves from dying.
So as we enter the 24th century we see this guy named McKenna on Terra who has this new ship built the TAS Dreadnought the first real combat warship and he plans on using it, but first he takes it on a bit of a cruise to work out the bugs, all over people are still fighting kinda doing the whole Game of thrones thing with each other and then in 2314 the Terran Alliance starts bickering with itself again.. McKenna puts up with it for two years hoping they'll all stop being kiddies and put their big boy pants on but when they refuse he parks the Dreadnought over the top of Terra and basically goes and does a Lanaster on the Alliance government 'Either fall in line and make me boss or you can have me use it'.. he becomes the next big wig expands the Terran borders out a bit does a name change to the Terran Hegemony and by 2319 all the primary players for the next 700 years are in place.
Rather then peace though humanity shows its normal tendencies and the Age of war begins eventually the Cameron family gets in charge of the Terran government, the Laio's make this cool treaty called the Ares Conventions which they thought would kinda stop people being killed but instead it just makes war a little more formal and things are all going to pot as the Houses all start smashing each other and they basically continue to do this for oh a long while all the way into the 25th Century actually when during a war and a battle that the Terran's are loosing they suddenly show the secret project they been working on, a two legged walking tank they dub the Mackie.. and they use it.. and wipe the field, the Battlemech has been born.
Well the houses aren't happy with this and they all go well beep if we don't' do something we all gonna be screwed so hard we could reach lightspeed, so they lie, cheat, and well steal with the best of them and get the plans. This leads to the first Battlemech on Battlemech combat and things continue to go to pot for a while until the Cameron family who rule Terra go 'screw this, I'm a dreamer, I'm a believer.. If I Imagine hard enough I can see.... ' and he talks with the Mariks of the Free Worlds League and they make a treaty they then rope the Laio's in.. and eventully the Lyrian's and well we see the Birth of the Star League in 2556 a few years later the Federated Suns join because Cameron and Marik are whily players who manipulate the markets and then at last the Draconis Combine..
So by now humanities been in the stars for about 500 years and yeah they are still clubing each other you'd think it'd stop right? They all united the grand Star League and if you believe the Rose Tinted 3025 look back you might believe that to be the case, but nah.. First thing they do after all the dust of their new alliance is settled? Start another war! yeap see out on the edges of known space are these little independent nations called the Periphery states and they kinda like their independence their a bit like us Aussies, nah were good mate we don't want to join your gang, just leave us be and we'll leave you be, only Camerons like 'Nah uh.. your either with us ... or your against us' and well the Periphery goes bring it on.. this leads to the Reunification War in 2575 and well the League gets its butt handed to it at first but when you have the Economic might of well the US if we use modern day analytics you just go 'ok push through' and while were at it seed the seeds to our own doom.
Anyway they go out and forcefully make the Periphery join the League but in doing so they kinda cause a tin pot dictator who'd supported them by the name of Amaris to almost get murdered by his own people and yeah he ends up holding a gruge that goes through generations to come.
Cue the next 100 or so years and Humanity generally bickers but gets along and they get Tech to a level unseen before (and won't be seen again until the Clans turn up but that's future).
Anyway tensions rise but are generally going ok until 2750 when the head of the Star League and Terran Heg Simon Cameron goes on a tour to try and smooth things over, what he didn't plan on was that Amaris guy's family having a long memory and while no one can prove it he has an accident in 2751 and dies leaving his Baby kid the now ruler of the League and the head of the most powerful military in existence the Regent, his names Aleksandr Kerensky and well he'd likely have been a great guy and all except he's busy trying to stop the Star League falling apart and way to busy to be a dad... So the House Lords they use it to their advantage pass some laws and start ripping off the Periphery and the current head of the Amaris clan Stefan he starts weasling in with Richard Cameron the kiddy ruler of the League. Move on to 2762 and he comes of age, and Amaris begins to play his hand he stirs up a full on rebellion in the uppity Periphery and then a short while later in 2765 he does the ultimate Game of Throne and holds a Red Wedding of his own, killing every known Cameron (except possibly one but spoilers) and then declares himself king.
Well Aleksander doesn't like this idea at all, I mean his just failed at his job right? The houses are all like eh.. nah we really don't want to help ya that much mate (except the Drac's but they get black mailed) and he goes well screw this I've the biggest army in the galaxy and I'm gonna use it, first he takes Amaris's own nation and uses it to supply the Star League Defence force, then he launch's a bloody campaign to retake Terra and well he actually manages it by 2779 He's taken Terra back, killed Stefan and things can go back to how they where right?
Nah the House lords are all bickering and strip him of his position and title, they put this buy called Jerome Blake in charge of the Communications ministry because they want their fancy communications network to all work cause horse and pony sucks, and then to cap the cake they start poaching from the SLDF while Kerensky's busy trying to rebuild a nation!.. This really doesn't jive with him and he asks them nicely to stop, they basically laugh and go 'nah dude' so he throws a hissy fit gathers most of his troops, their families and says screw ya all i'm leaving.. taking about 80% of the mightiest Army in the universe and leaving in what they call Operation Exodus in 2784 and in doing so, he removes the only thing stopping the gates of hell from being opened. The house lords all basically go Nah I'm first' and when none of the others say yeah your right you are.. They cut sick on each other, Nukes, Chems.. you name it they use it as they go about clubbing themselves back to near stone age in what will be the First and Second Succession Wars. Blake goes 'ahh shoot' and uses what is left of the SLDF to take over Sol and make ComStar who later will become religious nut jobs and eventually the two big wars petter out only ComStar doesn't like this they start a Third one but this time the Houses are all like.. nah we need to stop killing Jump Ships and the like so no nukes and we will just use Battlemech's, go all Medieval style ok?
We join at the closing days of this the THIRD succession war the houses have kinda stopped the whole nuke thing Battlemech is king.
Welcome to the 31st Century.
Up until about 1997 our two universes are fairly close together, shortly after the collapse of the USSR however things change as we see the Russian government over thrown, a new cold war start followed by the formation of the Western Alliance and generally a lot of civil war in Russia. In 2017 the first ship is sent to Mars, and a year later two scientists named Takayoshi Fuchida and Thomas Kearny begin publishing a bunch of works that basically says you can punch a hole in space and time, however they get made out to be nut jobs and laughed at. By 2020 we have fusion reactors and by 2086 when the Terran Alliance forms things are getting fairly busy in SOL but tensions are rising as we close out the 21st Century.
Into the 22nd those two nut jobs every one laughed at and who died in obscurity? Well two years into the new century they are proven right and a year later the Terran Alliance start the Deimos project to make their Hyper Space drive a reality the science community eats some humble pie and name it after the two people they abused and call it the Kearny-Fuchida drive installing it into a ship called the TAS Pathfinder it goes for a small hop to Tau Ceti and by 2110 Humanity has it's first outpost on the imaginatively named 'New Earth' problem is though that things are about to become really busy as people want well away from the over bearing dolts on earth so they start slapping jump engines on anything they can for the next 20 years... Until some one forgot to put the carbie on the Liberator right and it kinda just vanishes.. Leading the boys in charge to get a bit annoyed at the loss of life and make the Colonisation Procedure which basically says 'you have to have an escort from the new Terran Space Navy and a few other things', it doesn't really change much though people are all like screw you we want out and by the time the first Survey/Census to find out how many systems they can exploit, er I mean help grow in 2174 humanity's already on a hundred plus systems and growing but that leads to some Cartel's forming and this mad family named Liao's start to power they do some cleansing on earth and well have to leave in a hurry.
Anyway things continue to grow and groups start to form until about 2234 when a few of the colonies begin to get a little jack of the overbearing Terran Alliance constantly coming over drinking all the booze, eatting all the pizza, throwing parties and refusing to help pay the bill for the repairs after and Denebola decides 'screw this' and declares independence, thing is they aren't the only one's sick of it and rebellion leads to the war of independence the Terran Alliance is all we will crush you, only they are about as useful as a 4 Barrel Holly carb on a 3 cylinder engine and get sent home with their tails between their legs, in response the alliance throws a hissy fit around 2238 because the Liberals get into power back on Terra and throw the bath water out of the tub telling the colonies their all ungrateful sods and that if they don't want Terra to help them and even if they do too bad, they aren't getting any help no more. They then limit themselves to about 1 jump from earth (30 LY). This leads to a lot of resentment and not a few deaths because well not every colony is self supporting for a start but also sees the birth of what will be what are now in 3025 the great houses because they all need to kinda come together to stop themselves from dying.
So as we enter the 24th century we see this guy named McKenna on Terra who has this new ship built the TAS Dreadnought the first real combat warship and he plans on using it, but first he takes it on a bit of a cruise to work out the bugs, all over people are still fighting kinda doing the whole Game of thrones thing with each other and then in 2314 the Terran Alliance starts bickering with itself again.. McKenna puts up with it for two years hoping they'll all stop being kiddies and put their big boy pants on but when they refuse he parks the Dreadnought over the top of Terra and basically goes and does a Lanaster on the Alliance government 'Either fall in line and make me boss or you can have me use it'.. he becomes the next big wig expands the Terran borders out a bit does a name change to the Terran Hegemony and by 2319 all the primary players for the next 700 years are in place.
Rather then peace though humanity shows its normal tendencies and the Age of war begins eventually the Cameron family gets in charge of the Terran government, the Laio's make this cool treaty called the Ares Conventions which they thought would kinda stop people being killed but instead it just makes war a little more formal and things are all going to pot as the Houses all start smashing each other and they basically continue to do this for oh a long while all the way into the 25th Century actually when during a war and a battle that the Terran's are loosing they suddenly show the secret project they been working on, a two legged walking tank they dub the Mackie.. and they use it.. and wipe the field, the Battlemech has been born.
Well the houses aren't happy with this and they all go well beep if we don't' do something we all gonna be screwed so hard we could reach lightspeed, so they lie, cheat, and well steal with the best of them and get the plans. This leads to the first Battlemech on Battlemech combat and things continue to go to pot for a while until the Cameron family who rule Terra go 'screw this, I'm a dreamer, I'm a believer.. If I Imagine hard enough I can see.... ' and he talks with the Mariks of the Free Worlds League and they make a treaty they then rope the Laio's in.. and eventully the Lyrian's and well we see the Birth of the Star League in 2556 a few years later the Federated Suns join because Cameron and Marik are whily players who manipulate the markets and then at last the Draconis Combine..
So by now humanities been in the stars for about 500 years and yeah they are still clubing each other you'd think it'd stop right? They all united the grand Star League and if you believe the Rose Tinted 3025 look back you might believe that to be the case, but nah.. First thing they do after all the dust of their new alliance is settled? Start another war! yeap see out on the edges of known space are these little independent nations called the Periphery states and they kinda like their independence their a bit like us Aussies, nah were good mate we don't want to join your gang, just leave us be and we'll leave you be, only Camerons like 'Nah uh.. your either with us ... or your against us' and well the Periphery goes bring it on.. this leads to the Reunification War in 2575 and well the League gets its butt handed to it at first but when you have the Economic might of well the US if we use modern day analytics you just go 'ok push through' and while were at it seed the seeds to our own doom.
Anyway they go out and forcefully make the Periphery join the League but in doing so they kinda cause a tin pot dictator who'd supported them by the name of Amaris to almost get murdered by his own people and yeah he ends up holding a gruge that goes through generations to come.
Cue the next 100 or so years and Humanity generally bickers but gets along and they get Tech to a level unseen before (and won't be seen again until the Clans turn up but that's future).
Anyway tensions rise but are generally going ok until 2750 when the head of the Star League and Terran Heg Simon Cameron goes on a tour to try and smooth things over, what he didn't plan on was that Amaris guy's family having a long memory and while no one can prove it he has an accident in 2751 and dies leaving his Baby kid the now ruler of the League and the head of the most powerful military in existence the Regent, his names Aleksandr Kerensky and well he'd likely have been a great guy and all except he's busy trying to stop the Star League falling apart and way to busy to be a dad... So the House Lords they use it to their advantage pass some laws and start ripping off the Periphery and the current head of the Amaris clan Stefan he starts weasling in with Richard Cameron the kiddy ruler of the League. Move on to 2762 and he comes of age, and Amaris begins to play his hand he stirs up a full on rebellion in the uppity Periphery and then a short while later in 2765 he does the ultimate Game of Throne and holds a Red Wedding of his own, killing every known Cameron (except possibly one but spoilers) and then declares himself king.
Well Aleksander doesn't like this idea at all, I mean his just failed at his job right? The houses are all like eh.. nah we really don't want to help ya that much mate (except the Drac's but they get black mailed) and he goes well screw this I've the biggest army in the galaxy and I'm gonna use it, first he takes Amaris's own nation and uses it to supply the Star League Defence force, then he launch's a bloody campaign to retake Terra and well he actually manages it by 2779 He's taken Terra back, killed Stefan and things can go back to how they where right?
Nah the House lords are all bickering and strip him of his position and title, they put this buy called Jerome Blake in charge of the Communications ministry because they want their fancy communications network to all work cause horse and pony sucks, and then to cap the cake they start poaching from the SLDF while Kerensky's busy trying to rebuild a nation!.. This really doesn't jive with him and he asks them nicely to stop, they basically laugh and go 'nah dude' so he throws a hissy fit gathers most of his troops, their families and says screw ya all i'm leaving.. taking about 80% of the mightiest Army in the universe and leaving in what they call Operation Exodus in 2784 and in doing so, he removes the only thing stopping the gates of hell from being opened. The house lords all basically go Nah I'm first' and when none of the others say yeah your right you are.. They cut sick on each other, Nukes, Chems.. you name it they use it as they go about clubbing themselves back to near stone age in what will be the First and Second Succession Wars. Blake goes 'ahh shoot' and uses what is left of the SLDF to take over Sol and make ComStar who later will become religious nut jobs and eventually the two big wars petter out only ComStar doesn't like this they start a Third one but this time the Houses are all like.. nah we need to stop killing Jump Ships and the like so no nukes and we will just use Battlemech's, go all Medieval style ok?
We join at the closing days of this the THIRD succession war the houses have kinda stopped the whole nuke thing Battlemech is king.
Welcome to the 31st Century.
