Liberty and Piety work as a perfect combination for the Byzantines. If you can get Jesuit Education or Sacred Sites, you're going to have a very good time. I usually start Liberty with Byzantines because religion is best for wide empires. Getting a good 6-10 cities is nice, I would not recommend going in Tradition and just get monuments and libraries in your cities. Trade off any luxury for another or if you're low go on gold. Try to finish Liberty as fast as you can and I would recommend a Great Engineer to get a key important wonder such as Alhambra, Notre Dame, ect. Remember faith is everything for the Byzantines and you want it to spread as fast you can get it to. You want to get the 25-50% religious text and with your other bonus religion belief get the 30% spread for cities further away. For the other religion slots go for happiness faith buildings such as Cathedrals or Pagodas. If you're going for a culture victory and you get Sacred Sites, you're going to get around 35 Tourism from that alone. If you're go Jesuit Education then definitely produce anything but science buildings and let faith buy those. With 20% discount policy with Piety and your cities producing a ton of faith (get the holy site building) you can get them astonishingly fast, securing your dominance in science. Avoid going for Tradition, there will be no benefit as faith is not as useful for small empires, and you will be producing less faith too. I would also recommend getting Stonehenge right off the bat to secure your religion, if you're not going to get Stonehenge, go Liberty fast and go all Shrines in your cities, remember to get some workers out and trade gold/happiness with the AI well. I would also recommend trying to find as many AI's as possible and founding the World Congress and to propose World Religion (yours) as soon as possible. Use your spies as diplomats and give an okay amount to make sure the resolution passes. Of course, if you can squeeze Forbidden Palace out (Which also gives a happiness boost) this will help a lot.
If this works, you should dominate the rest of the game, especially with Jesuit Education. The Byzantines must focus on either religion or early war. Dromons are fantastic in the water and will crush any sea unit unless Frigates come in play. They get a 50% bonus for that. But you want your Dromons to focus on coastal capitals like Venices Great Galleass are designed for. If you can take an enemy coastal capital or two, you've kicked started your empire, I would recommend around getting four Dromons and a Cataphract to take the city. Otherwise do not try to combine religion and early war together, your GDP will not be good from all the maintence from your shrines, libraries and units. And you will be focusing more on producing those Dromons which will lack your faith even more. I would highly recommend the religion route as it secures your late game domination, hence Jesuit Education/Sacred Sites tourism.
