Why medieval naval commanders are hard to identify

Were there notable medieval naval commanders besides William de Leybourne?

Yes, but many are difficult to name because surviving accounts credit the king rather than the officer actually commanding at sea.

Medieval accounts often credited naval success to the king, leaving the person actually directing the ships difficult to identify. Research into operations involving the Teutonic Knights and Poland illustrates the need to recover scattered references. Edward I and Edward III stand out for acknowledging their naval commanders. Recovering those officers' names therefore depends partly on how rulers and chroniclers assigned credit.