Gerrit van Praag was a son of Meijer van Praag and Sara Frank. He married 24 August 1937 to his cousin Jogeva van Praag, daughter of Hijman van Praag and Elsje Oudkerk. The couple had a son, born in Velsen in November 1941 but he passed away, only 4 days old. In November 1942 they had another daughter who suvived the Holocaust.
City Archive of Amsterdam, archive card of Hijman van Praag and website wiewaswie.
Biography