Complex sentence: During the voyage, Ximénez lead a revolt in the which captain was killed, afer which mutineers landed near present day La Paz, on the southern tip of Baja California, which the mutineers believed to be the Island of California.
Split into simpler sentences: During the voyage, Ximénez lead a revolt in the which captain was killed. The mutineers then landed near present day La Paz, on the southern tip of Baja California, which the mutineers believed to be the Island of California.