During 1290, Mary's sister Elisabeth fled from Bohemia with her son because her husband had lost favour and was executed, Mary allowed Elisabeth and her son to stay in Naples with her, before she became a nun, but escaped and remarried to Stephen Uroš II Milutin of Serbia (brother of Catherine's husband) Elizabeth's stay in Naples is documented during July 1300. In 1294, Mary returned with Charles to Naples. She was his representative at the negotiations with the Pope in 1295-96. Between 1296 and 1298, she served as regent of Naples in the absence of her consort. She served as regent the last time in 1302. After this, she lost her influence over states affairs, and retired to pious duties such as to finance convents and churches.