Matthias of Trakai or of Vilnius (Latin: Matthias Vilnensis; Lithuanian: Motiejus Trakiškis; ca. 1370 – 9 May 1453 in Vilnius) was a Lithuanian Roman Catholic clergyman, the first Bishop of Samogitia from its establishment in 1417 until 1422 and the fifth Bishop of Vilnius from 4 May 1422 until 9 May 1453 and an ex officio member of the Council of Lords.
Matthias graduated the Charles University in Prague with the Master's degree in liberal arts in 1408, and studied in the University of Siena afterwards. Serving as the dean of Trakai, the Grand Duchy of Lithuania, he participated in the Christianization of Samogitia and was a supporter of Vytautas' political aspirations and an active participant in his coronation matters. Matthias was nominated to the newly established post of Samogitian bishop by Vytautas the Great and was consecrated on 24 October 1417 in Trakai.
Matthias was Samogitian and Lithuanian speaker. According to Jan Długosz, he was a Vilnian of Livonian German origin, while Vytautas himself has mentioned him being a Lithuanian. The bishop has conducted the marriage of King of Poland and Grand Duke of Lithuania Jogaila and 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 dying Vytautas on 27 October 1430.
Trakai ( Trakai (see names section for alternate and historic names) is a historic city and lake resort in Lithuania. It lies 28 kilometres (17 miles) west of Vilnius, the capital of Lithuania. Because of its proximity to Vilnius, Trakai is a popular tourist destination. Trakai is the administrative centre of Trakai district municipality. The town covers 497.1 square kilometres (191.9 square miles) of area and, according to 2007 estimates, is inhabited by 5,357 people. A notable feature of Trakai is that the town was built and preserved by people of different nationalities. Historically, communities of Karaims, Tatars, Lithuanians, Russians, Jews and Poles lived here.
The name of the town was first recorded in chronicles from 1337 in German as Tracken (later also used spelling Traken) and is derived from the Lithuanian word trakai (singular: trakas meaning a glade). Since the time of the Polish–Lithuanian Commonwealth, the city was known as Troki in Polish. Its other alternate names include Trok (Yiddish), Troky, and Traki.