The Zaccaria were at this time one of the leading families of Genoa, whither they had emigrated from the little Ligurian town of Gavi some two centuries earlier. The grandfather of Manuele and Benedetto, who derived his territorial designation of “de Castro,” from the district of Sta Maria di Castello, in which he resided, had held civic office in 1202; their father Fulcho had been one of the signatories of the treaty of Nymphæum[454]. Three years before that event Benedetto had been captured by the Venetians in a battle off Tyre. Three years after it, he was sent as Genoese ambassador to Michael VIII and, though his mission was unsuccessful, the Emperor had the opportunity of appreciating his business-like qualities[455]. Early in 1275, the year when Genoa had returned to favour at the Imperial Court, the two brothers started from their native city upon the voyage to Constantinople, which was destined to bring them fame and fortune—to Manuele, the elder, the grant of the alum-mines of Phocæa at the north of the Gulf of Smyrna, to Benedetto the hand of the Emperor’s sister[456]. Phocæa at that time consisted of a single town, situated to the west of the alum-mountains; but, later on, the encroachments of the Turks led its Latin lords to build on the sea-shore at the foot of the mountain a small fortress sufficient to shelter about fifty workmen, which, with the aid of their Greek neighbours, grew into the town of New Phocæa, or Foglia Nuova, as the Italians called it. The annual rent, which Manuele paid to the Emperor, was covered many times over by the profits of the mines. Alum was indispensable for dyeing, and Western ships homeward-bound were therefore accustomed to take a cargo of this useful product at Phocæa[457]. The only serious competition with the trade was that of the alum which came from the coasts of the Black Sea, and which was exported to Europe in Genoese bottoms. A man of business first and a patriot afterwards, Manuele persuaded the Emperor to ensure him a monopoly of the market by prohibiting this branch of the Euxine trade—a protective measure, which led to difficulties with Genoa. He was still actively engaged in business operations at Phocæa in 1287, but is described as dead in the spring of the following year[458], after which date the alum-mines of Phocæa passed to his still more adventurous brother, Benedetto.