Frederik Vorstenburg, born in Harlingen on September 5, 1882, son of Cornelis Vorstenburg (butcher and butcher's man) and Pietje Langedijk, butcher.

Frederik was married in Harlingen on November 14, 1907, at the age of 25 to
Jantje Bijlsma (aged 21 years), born in Dedgum on January 15, 1886.