Source: Records of St. Martin and St. Severus Catholic Church in Muenstermaifeld. Source of the date and the location of their marriage: Manfred Ruettgers.
The name on the baptismal register was Maria. Her baptismal sponsors were Philipp Esch and Maria Sevenich. Her marriage to Martin Oster required a dispensation because of 4th degree consanguinity. They may have been third cousins. Her father witnessed her wedding in 1738.
She was a baptismal sponsor in 1741 for Sebastian, the son of Johann Adams and Elisabeth Constantia Kieselbach of Muenstermaifeld; in 1742 for Johann, the son of Gertrud Kirchem and the late Emmerich Baur of Muenstermaifeld; in 1748 for Wilhelm, the son of Johann Hoeth and Anna Maria Schneeberg of Muenstermaifeld, and for Hermann, the son of her sister Lucie Port and Johann Heinrich Prum of Muenstermaifeld; and in 1754 for Matthias, the son of Johann Huenthen and Eva Bast of Muenstermaifeld.

Source: Records of St. Martin and St. Severus Catholic Church in Muenstermaifeld.
HIs name was sometimes given as Johann Martin Oster.
His baptismal sponsors were Rev. Martin Oster of Karlich and Anna Maria [Weckbecker], the wife of Matthias Michels of Muenstermaifeld. He was a synodalis in the Catholic church. His father Nikolaus Oster witnessed his wedding in 1738. At that time Martin was living in Muenstermaifeld.
Martin was a baptismal sponsor in 1731 for Eva Katharine, the son of his first cousin Josef Weckbecker and Eva Suesterhenn of Sevenich; in 1737 for Martin, the son of Franz Anton Kieselbach and Maria Margarete Merten; in 1738 for Anna Gertrud, the daughter of Anton Sevenich and Anna Maria Schmidt of Muenstermaifeld; in 1739 for Johann Martin, the son of Philipp Duemmelr and Anna Maria Camp; in 1741 for Martin, the son of Maria Magdalene Tilman and the late Heinrich Ackermann of Muenstermaifeld; in 1745 for Martin, the son of his wife’s first cousin Peter Port and Anna Margarete Mannebach of Muenstermaifeld; in 1749 for Katharine, the daughter of Heinrich Adams and Lucie Puelicher of Muenstermaifeld; in 1750 for Anna Maria, the daughter of his sister Katharine Oster and her husband Johann Oster; in 1751 for Martin, the son of his wife’s sister Lucie Port and Johann Heinrich Prum of Muenstermaifeld; in 1755 for Gertrud, the daughter of his wife’s second cousin Sebastian Puelicher and Margarete Mies of Muenstermaifeld; in 1765 for Maria Agnes, the daughter of Matthias Seul and Maria Elisabeth Gries; in 1767 for Anna Margarete, the daughter of Anton Kraemer and Maria Magdalene Sahns; in 1768 for Martin, the son of Matthias Heiken and Maria Elisabeth Kieselbach; in 1776 for Anna Maria Huerter, the daughter of Johann Heinrich Oster and Agnes Suesterhenn of Muenstermaifeld; and in 1779 for Susanna (?), the daughter of his wife’s niece Maria Margarete Prum and Johann Martin Schneeberg of Muenstermaifeld.
Martin witnessed the wedding of Johann Weckbecker and Anna Maria Oster in June 1781 in Gierschnach.