In spite of his iconoclastic sympathies, he endeavoured to conciliate the image-worshippers, but incurred the wrath of the monks by entering into a second marriage with Euphrosyne, daughter of Constantine VI., who had previously taken the veil.
In 1646 he was sent at the head of an extraordinary mission to France, and on his return married the queen's cousin Marie Euphrosyne of Zweibri cken, who, being but a poor princess, benefited greatly by her wedding with the richest of the Swedish magnates.
The attempt was unsuccessful and, after wandering about Greece, he surrendered with Euphrosyne, who had meanwhile joined him, to Boniface of Montferrat, then master of a great part of the Balkan peninsula.
Fru Julia Nyberg (1785-1854), under the title of Euphrosyne, was their tenth Muse, and wrote agreeable lyrics.
Euphrosyne again retired into a convent.