The Domesday Book of 1086 does not record Didcot. In 13th-century records the toponym appears as "Dudecota", "Dudecote", "Doudecote", "Dudcote" or "Dudecothe". Some of these spellings continued into later centuries, and were joined by "Dodecote" from the 14th century onward, "Dudcott" from the 16th century onward and "Didcott" from the 17th century onward. It is derived from Old English, meaning the house or shelter of Dudda's people. The name is believed to be derived from that of Dida, a 7th-century Mercian sub-king who ruled the area around Oxford and was the father of Saint Frithuswith or Frideswide, now the patron saint of both Oxford and Oxford University.