The Temple is of course one of the things to see in London, one of the oldest churches in the city, used to belong to Knights Templars (hence the name, though the knights are long gone). It is a characteristic church that crusader orders built in Europe, a rectangular church with a rotunda in the west (like the church of the Sepulchre in Jerusalem). The calligraphy is in the rectangular part, which is Gothic, obviously built later than the Romanesque rotunda. During the Cromwell era calligraphy instead of pictures were produced. Here is one of the best examples I know: a prayer written in antiqua calligraphy, with even shadows added to each letter, and framed like a picture. Apparently in England for a time it was a custom to frame prayers like pictures and hang them in churches.
