Ridder Jacob Westerbaen (7 September 1599 – 31 March 1670), heer (squire) of Brantwyck-en-Ghybelant, was a Dutch poet.
Westerbaen was born in The Hague, the son of a rope maker, and was initially schooled in the Staten-College, then as secretary and preacher of the Remonstrants of the Synod of Dort. There he studied medicine, after which he established himself in 1623 as a physician in the Hague. Two years later he married Anna Weytsen, the widow of Reinier van Groenevelt, despite opposition from her noble family.
He was a good friend of Constantijn Huygens. Later he came into contact with Jacob Cats, Blasius (1639—1672) and Jan Vos (ca. 1610—1667), becoming good friends with all three. When Oldenbarnevelt was executed for political reasons, Westerbaen retained possession of the victim's walking stick, inspiring the Republic's great poet, Vondel, to his famous poem 't Stockske ("The Little Walking-Stick").
Westerbaen wanted to apply for work elsewhere: Ockenburgh near Loosduinen, where he lived from 1652 until his death. He described it in a poem imitating the style of Huygens.
He fought fiercely against orthodox preachers, for instance in writings such as Krancken-Troost voor Israel in Holland ("Comfort for a Sick Israel in Holland") and wrote and translated plays, mostly comedies.
He also worked on the Heroides of Ovid and the Basia of Janus Secundus.
1. eren = ploegen.