If by 'early Christians' you mean the first wave of converts following the Augustinian mission of 597, rather than the first Romano-British Christians then the answer is a qualified yes. The Anglo-Saxons were well aware of the Classical world and its legacy. The British Library contains an early eleventh century mappa mundi from Canterbury which, although slightly janky by modern standards and hopelessly lost when it comes to most of Asia, does have a relatively high level of accuracy for much of Europe and the Mediterranean, with major sites like Jerusalem, Rome, Antioch and Alexandra all roughly speaking in the right places.