What's the flag of the country Juan ponce de Leon dis exploration for?

Juan Ponce de Leon did exploration for SPAIN.

He was comissioned as governor of Puerto Rico by King Ferdinand. In 1513, Ponce de León led the first known European expedition to La Florida. He returned to Spain in 1514 and was knighted by King Ferdinand, who also reinstated him as the governor of Puerto Rico (he got into problems with Diego Columbus - son of Christopher Columbus - who took away from him the government from Puerto Rico for almost two years) and authorized him to settle Florida