Complex sentence: Since Valero de Bernabé had developed anti-monarchist feelings following his experiences in Spain, he revolted against Iturbide; as a result he fled the country but was captured by a Spanish pirate who turned him over to the Spanish authorities in Cuba, where he was imprisoned.
Split into simpler sentences: Since Valero de Bernabé had developed anti-monarchist feelings following his experiences in Spain, he revolted against Iturbide. It did not succeed and he fled the country, but was captured by a Spanish pirate who turned him over to the authorities in Cuba, where he was imprisoned.