San Giovanni Evangelista, Ravenna

It was built in the fifth century AD by the Roman imperial princess Galla Placidia[1] "in fulfilment of a vow made by her to S. John Evangelist, when, on her way from Constantinople to Ravenna, she was in danger of shipwreck.

Agnellus tells us that of old the church bore an inscription to this effect, and he gives it to us: Sancto ac Beatissimo Apostolo Johanni Evangelistae Galla Placidia Augusta cum filio suo Placidio Valentiniano Augusto et filia sua Justa Grata Honoria Augusta, Liberationis periculum maris votum solvientes.

In the 14th century both the church and the monastery were renovated in the Gothic style: of that intervention the portal is visible today.

In 1747 the church was almost entirely stripped of its mosaics; the only two remaining fragments of the original 5th-century floor record the first Christian use of hooked crosses.

Other mosaic fragments found surviving the WWII bombing belong to the 13th-century floor and depict the Fourth Crusade.