The painting shows Emperor Matthias (1557–1619) in coronation regalia as King of Bohemia. Under his cloak he wears an Ottoman robe of honor, the hi'lat, decorated with peacocks.
Hans von Aachen (1552–1615), Emperor Matthias as King of Bohemia, c. 1611/12, oil on canvas, 184.5 x 116.5 cm; source: © akg-images, Inv. No. HS 310 (previously PHO 304) https://www.akg-images.de/archive/-2UMEBMYM97U9I.html, Prague, art collections of Prague Castle.