Jacob Kooi, born in Kollum on December 22, 1874, son of Popke Kooi (baker) and Frouwkje Smeding, blacksmith, died in Purmerend on July 21, 1948, aged 73 years.

Jacob was married in Kollumerland on May 5, 1900, at the age of 25 to
Antje Feenstra (aged 26 years), born in Wartena on March 10, 1874, daughter of Wytze Gerrits Feenstra (barge hand, merchant and shopkeeper) and Grietje Martens Veenema, died in Venhuizen on December 22, 1952, aged 78 years.

• 1 : Popke Kooi, born in Sint Annaparochie on April 8, 1901.
  

• 2 : Wijtze-Gerrit Kooi, born in Sint Annaparochie on May 28, 1902.
  

• 3 : Thomas Kooi, born in Sint Annaparochie on July 8, 1904, died in Purmerend on September 9, 1920, aged 16 years.
  

• 4 : Grietje Kooi, born in Sint Annaparochie on June 28, 1906.