The name ''Korea'' derives from the name ''Goryeo''. The name ''Goryeo'' itself was first used by the ancient kingdom of Goguryeo, which was considered a great power of East Asia during its time, in the 5th century as a shortened form of its name. The 10th-century kingdom of Goryeo succeeded Goguryeo,and thus inherited its name, which was pronounced by the visiting Persian merchants as "Korea". The modern name of Koreia, appears in the first Portuguese maps of 1568 by João vaz Dourado as ''Conrai''  and later in the late 16th century and early 17th century as Korea (Corea) in the maps of Teixeira Albernaz of 1630.