The Cod faction generally consisted of the more progressive cities of Holland. The origin of their name is uncertain; perhaps it derives from the arms of Bavaria, that look like the scales of a fish.
The Hook faction consisted for a large part of the conservative noblemen.
After count William IV of Holland was killed in 1345, his sister
Margaret of Holland inherited the county. She was married to emperor
Louis IV of Bavaria, and resided in
Bavaria. She appointed their second son William (the later count
William V of Holland) as ruward of Holland, which meant that he
ruled as her representative.
In 1350, the nobles of Holland asked Margaret to return to Holland.
As a reaction, the Cod league was formed in May 23, 1350 by a
number of supporters of William. On September 5 of the same year,
the Hook league was formed. Soon afterward, these factions clashed, and
a civil war began.
Edward III, Margaret's brother in law, came to her aid, winning a naval engagement off Veere in 1351; a few weeks later the Hooks and their English allies were defeated by William and the Cods at Vlaardingen, an overthrow which ruined Margaret's cause. Edward III shortly afterwards changed sides, and the empress saw herself compelled (1354) to come to an understanding with her son, he being recognized as count of Holland and Zeeland, she of Hainaut. Margaret died two years later, leaving William, who had married Matilda of Lancaster, in possession of the entire Holland-Hainaut inheritance (July 1356).
Although there were a number of smaller fights in the period after 1356, the main battle re-emerged at the death of count William IV of Holland in 1417. Both William's brother John and his daughter Jacoba claimed the county. The Cods chose the side of John, and, after his death, of Philip the Bold of Burgundy, while the Hooks supported Jacoba.
The result of these battles was that Jacoba was allowed to retain the title of countess, but that Philip would rule the county. Philip was named heir to the county, and Jacoba, who was childless, was not allowed to remarry without Philip's consent.
The treaty became void when Jacoba remarried in 1432, and she had to hand her territories over to Burgundy.Margaret of Bavaria vs William V
Jacoba of Bavaria vs Philip of Burgundy