In earlier work devoted to Feliks Nowowiejski, detailed information concerning his family is lacking. It was only thanks to a query in the Archives of the Archdiocese of Warmia in Olsztyn that many new facts about the ancestors of this outstanding composer were established, as well as a complete list of his brothers and sisters. It turns out that Feliks Nowowiejski's father Franciszek Nowowieski (whose name was recorded in the books), married first Monika from Ratzki, with whom he had seven children. The last one was born dead, and two days later the mother also died due to cholera (16.09.1866). The second marriage was concluded on 18 February 1868 with Catherine from Falk. In this relationship, eleven children were born, including Feliks - on February 7, 1877. When the first child was born, Felik's father (Francis Nowowieski) was 25 years old, and when the last child was born, 64 years old. The age difference between the first and last child in the Nowowieski family was 39 years, and by the time of the second marriage only the birth of the first child and the last twenty-six years had passed. At least five siblings from the second marriage were musically talented and pursued their vocation in life in this field. Besides Feliks, they were Maria, Rudolf, Leon and Edward. Feliks was in fact the most celebrated out of all of them and his 140th birthday is celebrated in 2017.