The Alcazar - Segovia (near Madrid, Spain)
"The Alcazar commands a strategic outcropping of the city's plateau high above the juncture of two small rivers. It is, of course, everyone's personal castle in Spain. Built in the eleventh century and rebuilt in the early fifteenth, it has a dashing, even romantic intimacy with its site that is difficult to equal. Muslim influence is seen in the name and in the building itself, particularly the interior."
— G.E. Kidder Smith. Looking at Architecture. New York: Harry N. Abrams, 1990. p80.
Fletcher says 1410 to 1455.