I realize my game is in the early stages for this thread, but technically the Byzantines start as an Empire, so ...
Yes, this might be the luckiest ever Byzantium DW start. This is a 1405 start, not 1399. All settings are default. How did this happen? Well, before unpausing, sent Alliance to Trebizond, DoW Turks, and sent my little boats to try and hold the strait.
Hold the straits they did. In 1405, the Turks west of the Bosphorus are almost completely sieged by rebels. It was actually quite easy to step all over them. The Turks had a huge army, tho, and refused to peace out.
So I just sat on it until I think it was the Mamlukes and Ak Koyunlu (whatever their name is) were both at war with the Turks, then I Call to Arms Trebizond (they had agreed) and within a month Candar and Karaman are also jumping the Turks. They are devestated, but hold onto their side of the Bosphorus - I peaced out and took everything on my side from them in the middle of their smack down. Candar and Karaman took all of the rest of the Turks, I think, but Ak Koyunlu might have taken a piece.
During that time, I had gotten cocky and DoW on Achaea. Stomped them quickly and easily, but was now at war with a good 20% of Europe. I was doing my very best to just stay alive, when something happened to Venice's fleet. I have no idea what, but it was farking gone. So I just blockaded (figuratively) my own coast and pieced out with Hungary (paid through the nose, but only Ducats.) Somehow, I survived all of that, and lucky me, Athens had joined the fighting at some point as did Corfu and Naxos. I took all three of those, tho I took a hard Infamy hit since they were defenders. Still, they were all cored.
I ended up getting some kind of CB on Wallachia, don't recall it, and ended up annexing them accidentally. Studying for bar exams while playing EU3 is probably a bad idea for both endeavors. I got a mission to vassalize Serbia, so I did. Hungary DoW me at some point, no idea why, and nobody came to help them other than their PU/vassal (don't recall which) Transylvania. I stomped Transylvania and was fighting a defense war with Hungary whilst Serbia was sieging about 40% of Hungary. Then, my saviors - Bohemia DoW Hungary and RUNS THEM OVER, forcing the release of Transylvania, who I promptly annexed, but that was a mistake again. I thought about releasing them and Wallachia, but I was holding on to things. I grabbed a couple provinces from Hungary (Bosnia/Dalmatia) and cut Hum off from them, which almost immediately revolted and formed Bosnia (as planned). At some point Janina revolted from Naples, I DoW on them (since everyone else had and I figured it was safe) and I won the race to get there first. Annexed with no Infamy. Same exact thing happened with Albania within a year.
Recently I fought a defensive war with Candar/Karaman/Mamlukes, and as you can see, I came out on top - Tripoli ended up DoW Mamlukes in the middle of it, pulling the heavy hitters away and letting me mop up Candar/Karaman.
Of course, my infamy is a BIT high now, and I am salivating over Ragusa and Bosnia, as well as Rhodes (eeek, Castille!) and Cyprus...
Any thoughts on where to go next?
Oh, and 1425 - Theme System in place. Talk about wild ride so far!
Luckiest. Byzantine. Start. EVAR.
*EDIT: Just noticed that France and Castille are enjoying Regency Councils, while Cyprus and The Knights (Rhodes) have no allies (The Knights are in Castille's sphere of influence while Cyprus is in France's). DoW, away! And these will net no infamy! Hah!