Maximillian I of the Holy Roman Empire (1459-1519) appointed Lukas Fugger vom Reh as the ‘titular’ king of Atlantis in 1499. The certificate of appointment nominated the Azores as the remnants of Atlantis. This could have been considered a provocative act by the Portuguese, who controlled the Azores, as their principal rivals, the Spanish, had allied themselves through marriage with Maximillian the previous year. Leaving the politics aside, this event indicates that Maximillian accepted the reality of Atlantis and placed it in the Atlantic.
This very early reference to Atlantis is covered in greater detail on the excellent Atlantisforschung.de website(a), who got the information from Markus Fugger von dem Rech, a descendant of Lukas. We are indebted to Thorwald C. Franke for the first mention of this in English(b).