Complex sentence: The exact circumstances are vague as to the reasons behind his becoming a corsair, however he "was made welcome as an enemy of the Spaniards" and had become one of the taiffe's leading reis within three years of his arrival.
Split into simpler sentences: The exact circumstances are vague as to the reasons behind his becoming a corsair. However he "was made welcome as an enemy of the Spaniards" and had become one of the taiffe's leading reis within three years of his arrival.