Willem Janszoon (or Jansz.) Blaeu (1571 - 1638) was the founder of a large publishing firm that became famous in the field of cartography under the name Blaeu. The Blaeu family has its origin on the island of Wieringen, where around 1490, Willem Jacobsz., alias Blauwe Willem, the grandfather of Willem Jansz. Blaeu was born. From the marriage of Willem Jacobsz. and Anna Jansd. came six children.
The son Jan Willemsz. (1527- before 1589) was the
father of Willem Jansz Blaeu, who continued
the family tradition by practising the trade of herring packer. In his
second marrariage with Stijntge. Willem Jansz Blaeu was born
We do not know wether he was born at Alkmaar or Uitgeest.