Mr. Morgan's book 'The Place-names of Wales' (1912) tells us the origin of the name Pontefract.
Pont is generally derived from the Latin pontem, a bridge. The monks were great bridge-builders, and it is supposed that they introduced the word to us. Pontage is a duty paid for repairing bridges. The Roman pontiff was so called because the first bridge over the Tiber was constructed and consecrated by the high priest.
Pontefract is a pure Latin name, from pons, a bridge, and frangere, to break, signifying a broken bridge, so called from the bridge breaking down when William, Archbishop of York, was passing over.