The VOC base in Mocha, today known as Al-Mukha, was opened in 1621. Trade there was severely curtailed by the volatile political situation. At first the VOC was subject to the Turkish overlords, later to the Arabic Yemenites, now freed from Turkish rule. The VOC attempted to force trade by violent means, to no avail. This foreign outpost only began to flourish in the early 18th century, boosted by the demand in Europe for Mocha's coffee. Until 1707 Mocha fell under the jurisdiction of the head office in Surat, but thereafter it came under Batavia as an independent base. In 1739 it was closed, although the VOC continued to sail to Mocha. Because the VOC ships coming to Mocha for coffee were dependent on the monsoon to sail, trade was slow to flourish. Arab traders drove the price up, knowing the ships needed to leave as soon as the wind turned favourable. However once the Company had established a permanent base, it was able to negotiate more attractive prices. Among the goods the VOC exchanged for Mocha coffee were spices, a narcotic called 'quat', and porcelain coffee cups.