Who gave the Gulf of Mexico its name and what year did they do it?

Question

Who gave the Gulf of Mexico its name and what year did they do it?

Answer 1

The Spanish.

The Gulf was unnamed until the early 1540s and was considered part of the Atlantic Ocean. The Spanish name most often applied to it was Seno Mexicano (seno="gulf" or "bay"), although it was occasionally referred to as Golfo de Nueva España, or Golfo de México. (7)

Answer 2

I have a Spanish nautical chart, written in LATIN that dates to about 1590 which mentions it... but the shoreline is WAY wrong and the mouth of the Mississippi River is too far East