This map shows the geographical location of four important ecumenical councils, including Constantinople, Chalcedon, Nicaea, and Ephesus. The first three are very close to each other geographically, which is not something that I was previously aware of. Ephesus is also not too far from these other cities. Notably, these are all reasonably within distance to Jerusalem, and perhaps a bit further from Rome but still manageable. Being geographically close to both each other and these other holy sites makes it an ideal location to have these councils.
