 According to the Bychowiec Chronicle, after the murder of Sigismund in 1440, Mykolas was among supporters of Casimir IV Jagiellon for the throne of Grand Duke.For such support, he was reinstated as Elder of Samogitia, but the Samogitians did not want to recognize Casimir's authority.As a compromise, Casimir granted a privilege affirming semi-autonomic status of the region and granting new freedoms to the nobles.