“ In 1196 he became duke of Swabia, on the death of his brother Conrad; and in May 1197 he married Irene, daughter of the eastern emperor, Isaac Angelus, and widow of Roger II., king of Sicily, a lady who is described by Walther von der Vogelweide as “the rose without a thorn, the dove without guile.” Philip enjoyed his brother’s confidence to a very great extent, and appears to have been designated as guardian of the young Frederick, afterwards the emperor Frederick II., in case of his father’s early death. ”

“ The hostility to the kingship of a child was growing, and after Philip had been chosen as defender of the empire during Frederick’s minority he consented to his own election. He was elected German king at Mühlhausen on the 8th of March 1198, and crowned at Mainz on the 8th of September following. Meanwhile a number of princes hostile to Philip, under the leadership of Adolph, archbishop of Cologne, had elected an anti-king in the person of Otto, second son of Henry the Lion, duke of Saxony. ”

“ E. Winkelmann, Philipp von Schwaben und Otto IV. von Braunschweig (Leipzig, 1873–1878) ; O. Abel, König Philipp der Hohenstaufen (Berlin, 1852) ; Regesta imperii. V., edited by J. Ficker (Innsbruck, 1881) ”