Gee, forgot about that thread, though I see that I actually should reply. I'm not sure anymore what have been said by anyone or what exactly I said everywhere and I'm too lazy to reread it all, but I'll try to reply as good as possible to your post Siena (I'll consider your 'prologue' and your 'epiulogue' as unwritten though

).
1. First of all I (probably, as don't remeber saying it) didn't said I 'think' it happened, I said 'it happened'. I was probably quoting P.Jasienica or W.Reddaway here as they describe the Lithuanian 'culture' as such in the 16th century. Also when I say they were ruthenized in 16th century I don't mean the ruthenization started there but was by that moment accomplished. The proces started already in the 14th century or even earlier.
Ruthenization is here aimed on language and literary culture obviously. Ruthenian literary tradition was much older (to my knowledge there is no Lithuanian literary tradition before the 19th century - meaning vernacular literature in Lithuanian) and was prevalent in the territories that Lithuanians conquered. It is a common event in history that the conquerors assimilate themselves within the culture of the conquered if that culture has a 'higher level', Culture means here obviously the language and literary tradition, religion and religious tradition, artistic tradition and historical tradition. It is obvious that Ruthenian culture was much older and more developed after 500 years of history than Lithuanian who don't even have a 'history' before ~1200.
Why is ruthenization important? Mostly because of the fact as it prevented polonization of Lithuania, Belarus and Ukraina and as it defined for the Lithuanian aristocracy which accepted the ruthenian culture (I wouldn't claim that peasants did the same but these are also not improtant here - no one asked peasant about their opinion anyway) a cultural and thus political autonomy. Lithuanian aristocracy used Ruthenian language and literary culture in official political correspondence with Poland after Lublin and not because they didn't knew Polish (most did) but because it guaranteed their separation. It didn't help the unity of the state obviously and eventually helped to destroy the Commonwealth.
An interesting sideview is though that if Lithuania remained fully independant with their nobles ruthenized as they were and with a hughe ruthenian population, it would be Lithuania which would become Russia and not Muscovy. Obviously that wouldn't be a Lithuanian state but a Russian one and probab;ly today there would be no Lithuanian culture at all.
And well, you ask me for definitions: so please define here a Lithuanian culture anno 1400. Or 1500. Or 1600. I want you to write a whole list of cultural achievements of medieval Lithuanians which were not Ruthenian/Russian from origine. When you manage to achieve that in a conceivable way you may call my statements (and these of respected historians from whom I derived it btw) 'nonsense'.
2. You get military and strategical/political weakness through eachother here. Lithuanians had some military advantages on their neighbours being the position of their corelands based in woods and their typically tribal and warlike organization which they shared in the 13th century with other balts. This worked very wel for a small, defensive state which was hard to reach and easier to defend. This didn't work in a large state consisting mostly of steppe and a civilized population that
with a non-tribal society.
Politically Lithuania was weak as its statehood was entirely based on conquest of territories of a higher culture of an old state it temporary decline, weakened by wars with mongols (Russia thus). It had here also for these territories no other opponents (Hungary was busy in the balkans, Poland started its interest in the east only in 2nd half of 14th century as before it was mostly fighting itself).
A separate issue were the Teutons. These sat there already since 12th century and had themselves enough problems with wiping out the tribal kingdoms of balts. This was due to lack of military and generally less usability of cavalry in Lithuania and Baltic lands. Lithuanians and other balts were generally able to send out more soldiers to the field and used better the territory to defend themselves.
YOu point of fighting and emails I don't get: read my post better. I don't deny that there was fighting but it was seldom anymore organized warfare but more raids. It is obvious indeed that Teutons had gave up conquest of whole Lithuania for the moment though it didn't stop them from trying to take it slice by slice (they did take samogithia after all in the 15th century).
Lithuanian strategical/political position was thus precair because it:
1. Was quite big but very decentralized as Lithuanians used themselves the apanage-system for the Russian duchies they conquered, various dynasties tried to secure the power for themselves;
2. There was no common cultural tradition originating in Lithuania, only the Ruthenian BUT that was not the culture of its rulers (who remained keeping up tribal customs but did not codify them). This did however separate the dukes and nobles from eachother and so helped the internal fractioning.
3. Lithuanian conquest was not so much based on the strong position of Lithuania but on the weakness of its enemies (don't come here again with Teutons as Lithuania did not expand there - this is actually another argument: Lithuania was only able to expand where it wasn't opposed; In the steppe it wasn't).
When the enemies reinstated themselves (Poland in 2nd half of 14th century, Russia/Muscovy in 15th century) Lithuanian state was thus in great peril from outside.
4. Lithuania was pagan and was as such not considered a true state and had no formal alliances. So it was as a Lithuanian state always inperil of wars in all fronts.
So in general a pagan Lithuania could have NEVER survived the 15th century alone: it had to either ally (and thus assimilate itslef to) Russia or Poland. The fact it that Lithuania lost a half of its lands to Muscovy in the 15th and early 16th century while it was actually still independant.
So again, I'm not denying the fact that Lithuania had in principle a good base for its military as long it was small, but it wasn't suited to survive as the big state that it was by 1400 in its pre 1400 form.
Teutonic Order had its own permanent members. Also, important part of their armies were locals - Prussians, Livonians and Estonians. And as time went by - they became suffieciently reliable.
Crusaders were very important too, of course.
Where did these permanent members come from you think?
And locals were used as 'cannonfodder', were unreliable and mostly used only to kill them. Teutons did not make local knights. Ah, and correct me if I'm wrong but afaik the knights of the Order were celibetary.
Kasperus says that "It is indeed diplomacy that caused eventually most of the TO-successes and not the military power".
Well then, how was Prussia conquered?
Most, not all, Prussians are an exception. But how were the Kurs, Ests, Zemgalese, Samogithians and all these other people conquered? By the use of diplomacy and quarreling these states against eachother. Zemgale fell to Samogithian and Lithuanian forces, Kurs were destroyed using Livonians and Zemgalese, Samogithia was destroyed by Teutonic and Lithuanian forces.
3. It wasn't done to save Lithuania (the Poles did not intend it at least, Polish first intentions were to stay independant of Luxemburgians and Hapsburgs and to have an ally against Teutons.), but it saved Lithuania nevertheless. It saved its identity (even if ruthenized) for later and it saved its independance because its ruthenian popuilation wouldn't be polonized. Finally it saved its political independance as Lithuania wasn't annexed by Russia in 15th century and within the union they were never entirely a part of Poland.
The claim that "Before Jogaila Lithuania did not own the Ukrainian lands at all" is false. Jogaila's father Algirdas accomplished that.
Prove that Algirdas conquered Kiev and Chernigov and Lithuania kept it till Jogaila's days and that Jogaila's Lithuania owned it before 1380. If they didn't own these cities they didn't own ukraine.
"Till 1506 at least Lithuania had always a duke who was a distinct person than the king" - statement by Kasperus, which is false. Look it up.
With exception of the rule of Kazimierz IV there was always an independant duke in Lithuania. And Kazimierz' is for a change the most Lithuanian-minded king that Poland ever had and spent most of his time in Lithuania.
"During some periods there was even no union at all (1434-1447 and 1492-1502) and was Lithuania governed directly by a duke sitting in Lithuania. Frankly Lithuania lost most of its power and territory in these days. " - statement by Kasperus, which is complete nonsense.
When was Lithuania divided into Russia?
Lithuania lost a half of its territory between 1400-1506 to Russia, while it regained parts of it between 1506-1632, thank you.
4.
. Russia
first lets define Russia. If Russia is Muskowy, then yes - Lithuanians were not their priority and vice versa.
However there were enough competition among them to keep their relationship very important.
Moskowy and Lithaunia were competing for influence over Novgorod, Tver and surrounding Russian duchies.
Mongols were also important to Lithuanians. Why would Mongols harras Russians, but ignore Lithuanians? For religious differences?
And your point is? WHo did conquer Novgorod eventually? Why didn't Lithuanians help it against Muscovy? Not because the Poles said them to not doing it but because Lithuania wasn't able to do ANYTHING against Muscovy. Tver and Novgorod tried to use Lithuanians against Muscovy but Liuthuanians proved to be useless allies.
"The whole Lithuanian conquest was one of entering the political vacum of non-existent Russian central govenment. " - Kasperus
OK, then what was Mongol conquest? Was it not the same?
.
Please, how was that vacuum created in the first place? Exactly, by Mongol conquest of Russia. Mongols had in early 13th century superior military with which they managed to destroy more centralized and stronger states than Russia. Lithuanian only conquests were against a non-existing Russia when the Mongol state was in decline. So no, it was not the same.