During his stay at Fort Bliss, von Braun proposed marriage to Maria Luise von Quistorp (born ), his maternal first cousin, in a letter to his father. He married her in a Lutheran church in Landshut, Bavaria on 1 March 1947, having received permission to go back to Germany and return with his bride. He was 35 and his new bride was 18. Shortly after, he became an evangelical Christian. He returned to New York on 26 March 1947, with his wife, father, and mother. On 8 December 1948, the von Brauns' first daughter together Iris Careen was born at Fort Bliss Army Hospital. The couple had two more children: Margrit Cécile, born 8 May 1952, and Peter Constantine, born 2 June 1960.