Charles Reginald Haines had produced an in depth study covering a variety of topics. A few of the topics covered include Invasion of Spain by the barbarians; Period of Gothic rule, Landing of Abdurrahman, Flora and Maria, Doubtful martyrs, Revolt of Spaniards against Arabs, Khalifate saved by Abdurrahman III, Arab factions, Traces of amalgamation of religions, Mutual influences of the two creeds, and Influence of Mohammedanism.