TheVitae Duorum Offarum is a work which professes to give a history of the foundation of St Albans Abbey. It has been ascribed to Matthew Paris, the famous historian and monk of that house, who died about the year 1259. Most scholars, however, now think that, though used by him, it was probably the work of an earlier writer belonging to the same abbey.

The Life of Offa the First is to the following effect. Once upon a time there was a king of the ‘West Angles’ (which probably means the Mercians here) whose name was Warmundus. He built the town of Warwick, which was called after him. At the time the story opens he was advanced in years and feeble. He had an only son named Offa, who was now thirty years of age. The latter had been blind until his seventh year and, though of great size and strength, he was still dumb and thus unfit to govern. One of the chief nobles, named Riganus, encouraged by another whose name was Mitunnus, endeavoured, first by entreaties and then by threats, to get himself adopted by the king as his successor. Having failed in these plans he had recourse to armed rebellion. Warmundus in view of the threatened danger called together his nobles to discuss what ought to be done. While all were in doubt Offa suddenly obtained the power of speech and demanded that his own and his father's rights should be preserved. He then offered to lead the king's forces, and the latter greatly encouraged by this event set out against the rebels.