 In 855 , Michael III turned fifteen and thus came nominally of age . His mother and Theoktistos both underestimated the young emperor 's desire to free himself from their custodianship , and antagonized him further when they arranged a bride show and selected Eudokia <unk> as his bride , disregarding Michael 's attachment to his mistress , Eudokia Ingerina . Theodora 's brother Bardas was able to use Michael 's resentment for the high @-@ handed manner in which he was treated and began to turn him against the regency . With Michael 's backing , Bardas was allowed to return to the capital , and on 20 November 855 , Theoktistos was murdered . Theodora was compelled to retire to a monastery a few months later , bringing the regency officially to an end . 
