Father Jan Sossalla (1908–1979) was a priest and amateur historian whose work focused on research on the history of the Church in Opole Silesia. Even though he did not hold university chairs or was professionally associated with scientific institutions, his contribution to preserving the traces of the Church's activity in this area is lasting. Jan Sossalla was born in 1908 in Chorzów, studied theology at the University of Wrocław, and then took a course for pastors of deaf people in Racibórz. After ordination as a priest, he worked as a vicar in various parishes and undertook doctoral studies in the history of the Church. His doctoral thesis concerned the secularization of the monastery in Neuhof near Kreuzburg in Silesia. In 1938, he was transferred to the parish in Wrocław, where he was also involved in pastoral work among the Polish community. After the period of vicariate, he was appointed administrator of the parish in Kluczbork, and then transferred to the parish of Corpus Christi in Miechowice, which in 1954 was incorporated into Bytom. He performed pastoral duties there until June 1978. During his pastoral work, Fr. Sossalla was actively involved in historical research, and his works mainly covered the history of the Church in Silesia. He cooperated with various researchers and took part in initiatives regarding the history of the Church in Opole Silesia. In 1978 he retired due to health reasons. He died in 1979 and was buried in the cemetery in Bytom-Miechowice. His scientific works left lasting traces in Silesian historiography, focusing mainly on sketches, contributions and material studies.