Willem Hiemstra, born in Wijnaldum on April 26, 1892, son of Herre Willems Hiemstra (worker and merchant) and Trijntje Robijns Tigchelaar (woman worker).

Willem was married in Barradeel on June 22, 1918, at the age of 26 to
Ynske Keizer (aged 25 years), born in Sint Jacobiparochie on November 25, 1892, daughter of Klaas Keizer (worker and workman) and Aafje de Jong.