The first or more detailed description of part of the coastline of Patagonia is possibly mentioned in a Portuguese voyage in 1511–1512, traditionally attributed to captain Diogo Ribeiro, who after his death was replaced by Estevão de Frois, and was guided by the pilot and cosmographer João de Lisboa). The explorers, after reaching Rio de la Plata (which they would explore on the return voyage, contacting the Charrúa and other peoples) eventually reached San Matias Gulf, at 42°S. The expedition reported that after going south of the 40th parallel, they found a "land" or a "point extending into the sea", and further south, a gulf. The expedition is said to have rounded the gulf for nearly 300 km (186 mi) and sighted the continent on the southern side of the gulf.[40][41]