Matthias was a Samogitian and Lithuanian speaker. According to Jan Długosz, he was a Vilnian of Livonian German origin, while Vytautas has mentioned him being a Lithuanian. The bishop has conducted the marriage of the King of Poland and Grand Duke of Lithuania Jogaila to his last wife Sophia of Halshany in the city of Navahrudak in 1422; he became the bishop of the Diocese of Vilnius later that year. Matthias sent representatives to the Council of Basel and set up the Inquisition to combat the Hussites, founded many churches and strenuously defended the rights and privileges of the Lithuanians. Matthias took care that new Catholic priests would be fluent in the Lithuanian language. He performed Last Rites for the dying Vytautas on 27 October 1430.