English seaman William Bourne publishes a manual, Inventions or Devises, Very Necessary for all Generalles and Captaines, as wel by Sea as by Land, including an early theoretical description of a submarine.
^In his Latin biography, Melchior Adam says that Gemma died on October 12, 1579, at the age of 45; modern scholars, however, almost uniformly cite 1578 as the year of his death.