Klaas de Groot, born in Pingjum on March 25, 1876, son of Klaas de Groot (worker) and Jeltje Robijns de Jong, worker.

Klaas was married in Wonseradeel on May 28, 1898, at the age of 22 to
Sijke Goslinga (aged 21 years), born in Pingjum on November 26, 1876, daughter of Tjerk Goslinga (worker) and Janneke Kuipers, maid servant.

• 1 : Klaas de Groot, born in Arum on March 7, 1899.
  

• 2 : Janneke de Groot, born in Arum on February 20, 1900.
  

• 3 : Tjerk de Groot, born in Arum on December 23, 1901.