Complex sentence: With Peter I also on board, as well as many distinguished noblemen and knights, the Castilian fleet set sail from Seville in April and sailed along the coast of Valencia, forcing the surrender of the Castle of Guardamar; it appeared before Barcelona on July 9.
Split into simpler sentences: With Peter I also on board, as well as many distinguished noblemen and knights, the Castilian fleet set sail from Seville in April. Traversing the coast of Valencia and forcing the surrender of the Castle of Guardamar, it appeared before Barcelona on July 9.