 After eleven years of negotiations which resulted in a renewed accord between the Empire and Genoa, Benedetto re-appeared in Constantinople with his brother Manuele in 1275.Benedetto married one of the emperor's sisters, while Manuele received control over the valuable alum mines of Phocaea.This was an extremely lucrative business, especially after Manuele acquired a near-monopoly after persuading Michael VIII to prohibit the import of alum from the Black Sea, even though this trade was also in the hands of Genoese merchants.