Regarding the flat Earth
There tends to be a common misconception that the earlier Christians and Church pushed the idea of the Earth being flat. I came by an interesting book called The Reckoning of Time by Bede the Venerable, which among other things related to how we understand time, calendar and certain cosmic events speaks about the shape of the Earth.
In the chapter called Why the same days are unequal in length Bede writes:
The reason why the same [calendar] days are of unequal length is the roundness of the Earth, for not without reason is it called 'the orb of the world' on the pages of Holy Scripture and of ordinary literature. It is, in fact, a sphere set in the middle of the whole universe. It is not merely circular like a shield [or] spread out like a wheel, but resembles more a ball, being equally round in all directions, but not in a mass of equal magnitude although I would believe that the enormous distance of mountains and valleys neither adds to it nor diminishes it any more than a finger would a playing ball.
...
Indeed, it is because of this same sphericity of the Earth that many of the most brilliant stars of the southern region are never seen by us. On the other hand, our northern stars are to a large degree concealed from them. Hence, the Trogodyte and his Egyptian neighbour do not see those polar stars which are straight over our heads, and which never set. In fact, not only we in Britain, but even the Italians cannot see their brightest star Canopus, which once was worshipped under the name of a god.
Interesting fact is that Bede is a western monk who lived in 7th and 8th century in England and is venerated as a saint in both Roman Catholic and Eastern Orthodox Church.