Vespucci's third voyage remains a subject of historical controversy to this day. Scholars have voiced serious doubts that it ever occurred. For Ringmann and Waldseemüller, however, who published Vespucci's letter to Pier Soderini on his four navigations in the appendix to the Cosmographiae Introductio of 1507, the voyage did take place, and it was one of the most important. In his letter, Vespucci writes that he outfitted a fleet of three ships and sailed from Lisbon on May 10 or 13, 1501. His third voyage was conducted at the request of King Manuel of Portugal (1469-1521), who was surely motivated by the news of Amerigo's discovery of lands east of the Tordesillas meridian. The expedition reportedly lasted 16 months. The fleet headed to the Canary Islands and, without stopping, continued along the West African coast to Cape Verde, at latitude 14°30' north. There, Vespucci met one of the ships of Vasco da Gama (1469?-1524), returning from the East Indies after circumnavigating Africa, and he reported the encounter to Lorenzo di Pierfrancesco de' Medici (1463-1503). After restocking necessary supplies, the fleet headed south-south-west, driven by the favorable trade winds. The ships also often sailed west along the Equator. After 67 days, including 44 of heavy storms, it reached land on August 17 at latitude 5° south. Because of clashes with natives practicing cannibalism, Vespucci set sail again for other shores, following the coast in a south-easterly direction. After 300 leagues, Amerigo realized he had passed a cape that he named Saint Augustine, at latitude 8° south. He continued down to latitude 52° south, where he observed a totally new night sky. Most of the constellations were unknown, and Vespucci measured them carefully, in the knowledge that the Southern Cross—already observed in Venezuela on the previous voyage—would give him a reliable means of identifying the Antarctic pole. As Lisbon lay at latitude 39° north and the fleet had reached latitude 52° south, Vespucci realized that he had navigated one-fourth of the Earth's circumference, that is, a 90° arc. On February 15, 1502, he sailed south to the open sea to avoid winds and currents, but the repeated storms and excessively long nights forced him to head back home. The fleet was just a few miles from the strait later passed by Ferdinand Magellan (1480-1521). Sailing north-north-east, Vespucci reached Sierra Leone on May 10. After a 15-day stopover and the destruction of a now heavily damaged ship, he returned to Lisbon with two ships, arriving on September 7, 1502.