It took way longer than I expected it to, but I finally finished my guide for Basil II from the New Frontiers' September 2020 update. It took a whole year for me to get around to this, but better late than never, I guess? The full guide can be found at my blog at: http://www.megabearsfan.net/post/2021/08/11/Civilization-VI-strategy-Basil-II-of-Byzantium.aspx A few highlights from the guide: Since Byzantine military units spread Byzantium's religion when they kill enemy units, Byzantium can send its Missionaries in one direction, and send its army in the other direction, and convert rivals on both sides. Byzantium should focus on converting holy cities early, which grants a combat bonus to both military and religious units, and makes both conquest and further conversions easier. Basil will also have a steady supply of free heavy cavalry units from the Hippodromes, which deal full damage to cities converted to Byzantium's religion. Byzantium can play for both religious victory and conquest victory at the same time. The Dromon can be a very useful unit for Byzantium. With 2 range, Galleys can shield the Dromon while it attacks enemy Galleys and Quadriremes without the Quadriremes being able to attack back. Killing enemy naval units behind the line can convert their cities before your land armies get there, and potentially convert their holy city, making it easier to conquer. Bbased on my testing, it appears that if Byzantium did not found its own religion, its units will spread the majority religion when they kill enemy units. However, if Byzantium did found a religion, its units spread Byzantium's founding religion, even if most of Byzantium's cities have been converted to another religion. This can be a way of re-converting your cities if you can defeat an invading force. Just use your units to deal the killing blows, since bombardment from walls does not seem to spread Byzantium's religion. Also, based on my testing, it appears that air units do not receive the bonuses from Taxis. They do not get combat bonuses, nor do they spread Byzantium's religion when killing units. I believe this is a bug, so hopefully it will be fixed by Firaxis at some point. Using military units to spread religion also frees up Byzantium to spend faith on things other than religious units, while still being able to convert rivals. And having free units mean you can pass on military beliefs like Warrior Monks. Taking beliefs like Jesuit Education, or dedication bonuses like Monumentality allows faith to be spent on infrastructure. The full guide contains plenty of other tips and tricks for playing as or against Basil II and Byzantium. I welcome any feedback, and I look forward to reading other players' tips and tricks as well. Thanks for reading, and happy Civ-ing!