Editing Hook and Cod wars (section)

=== A short war ===
The civil war now erupted in earnest. William of Bavaria's first moves were directed against the many castles that the Hook party held in Holland. Most of these were quickly conquered, others offered significant resistance. On 21 May 1351 [[Rosenburgh Castle]] surrendered after a violent siege. The count then moved on to take [[Polanen Castle]] in June 1351. In the same campaign, [[Binckhorst Castle]] was also taken after significant resistance. In the north [[Radboud Castle|Medemblik Castle]] offered significant resistance and was besieged in March-April 1351. 

On 15 May 1351 William succeeded in concluding a peace which ended the war with Utrecht, which had started in 1345. This was also important, because the parties would also evict each other's enemies from their territory.{{sfn|Van Mieris|1754|p=791}} Meanwhile, some of the stronger Hook castles could not be taken that quickly. [[Brederode Castle]] would only surrender on 23 October 1351. [[Oud Haerlem Castle]], owned by [[John II, Lord of Polanen|John II of Polanen]] would hold out into 1352. This also applied to [[Geertruidenberg Castle]]. Its [[Siege of Geertruidenberg (1351-1352)|blockade and siege]] would last from December 1351 to July 1352.{{sfn|Van Doornmalen|2017|p=96}}

On the other hand [[Edward III of England]], husband of Margaret's sister [[Philippa of Hainault|Philippa]], sent a fleet to Margaret's aid. This was initially successful. In May 1351 Margaret's combined forces won the [[Battle of Veere]]. Wolfert III van Borselen died soon after, but it seems that Margaret was not able to profit from her victory. I.e. Middelburg continued to hold William's side.

About six weeks later, the victorious Hooks and their English allies sailed up the Meuse. On 4 July 1351 they fought the [[Battle of Vlaardingen (1351)|Battle of Zwartewaal]] on the [[Oude Maas|Old Meuse]]. It was a clear victory for William and the Cods. The English admiral and many Hooks were killed. The outcome ruined Margaret's cause. William quickly moved south to start a [[Siege of Zierikzee (1351)]], which surrendered in October. 

In December 1351 Margaret hanged her last strongholds in Holland (Geertruidenberg Castle, the castle of Vreeland on the Vecht, and [[Oud Haerlem Castle]] near Heemskerk) over to King Edward, who changed sides soon afterwards.{{sfn|Blok|1923|p=325}} In February 1352 William married Edward's cousin [[Maud, Countess of Leicester|Maud of Lancaster]]. Margaret returned to Hainaut and did not succeed in rekindling the war.