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.