The Bishop of Dorchester was the head of the Anglo-Saxon Roman Catholic diocese of Dorchester, with his seat, or cathedra, at the cathedral in Dorchester-on-Thames in Oxfordshire.
The Bishop of Dorchester was the head of the Anglo-Saxon Roman Catholic diocese of Dorchester, or cathedra-on-Thames in Oxfordshire. This was at the cathedral in Dorchester. This was with his seat.