Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

French Huguenot explorer Jean Ribault charted the St. Johns River in 1562 calling it the River of May because he discovered it in May. Ribault erected a stone column near present-day Jacksonville claiming the newly discovered land for France. In 1564, René Goulaine de Laudonnière established the first European settlement, Fort Caroline, on the St. Johns near the main village of the Saturiwa. Philip II of Spain ordered Pedro Menéndez de Avilés to protect the interest of Spain by attacking the French presence at Fort Caroline. On September 20, 1565, a Spanish force from the nearby Spanish settlement of St. Augustine attacked Fort Caroline, and killed nearly all the French soldiers defending it. The Spanish renamed the fort San Mateo, and following the ejection of the French, St. Augustine's position as the most important settlement in Florida was solidified. The location of Fort Caroline is subject to debate but a reconstruction of the fort was established on the St. Johns River in 1964.
Who mapped the St. Johns River in 1562?