At the time, the Eastern Scheldt was the main branch of the Scheldt.,[1] which made Zierikzee a relevant sea-port.

In the early the middle ages, the islands of Schouwen, Duiveland, Dreischor, and Bommenede, which now form Schouwen-Duiveland were still separate.

[6] in which the Flemish fleet was largely destroyed and all claims of Flanders to Zeeland effectively ended, and Zierikzee came firmly under the control of the count of Holland.

During this turbid period slumbering tensions between conservative nobility and the cities whose independent power had been growing erupted.

On 31 August 1346 Margaret forbid subjects to communicate with Zierikzee and she openly called its citizens her enemies.

[7] By 1347, Zierikzee appeared to have made peace with the conservative noble fraction named the Hooks.

[9] The first Hook and Cod war started in earnest when Delft and other Holland cities rebelled in August 1350.

[11] In Februari 1351, letters arrived in Zierikzee stating that Gerard van Herlaer had freed her son from his Hainaut captivity, and that he had placed himself at the head of the Cod party.

[11] Margaret then went to Calais to enlist the help of England, taking the city councils of Dordrecht, Middelburg and Zierikzee with her.

They intended to fight Wolfert's Cod army, but this mostly deserted when it learned that Margaret had arrived.

[19] After their victory in the Battle of Veere, the Hook party probably attempted to first regain control of the whole of Zeeland.

[20] Margaret and her army then sailed north, but were severely defeated in the 3–5 July 1351 naval Battle of Zwartewaal.

The contemporary Antwerp secretary Jan van Boendale confirmed this by noting that William "chased his mother from Zierikzee with his army".

[26] The treaty was a cease-fire between the parties which would last up till and including 1 October (Saint Bavo day).

If Margaret and her army would enter Zeeland before 2 October and require Zierikzee to help her, the city would give William 8 days' notice before commencing hostilities.

On the other hand, the stipulation that the citizens could freely use their possessions 'everywhere',[28] implies that William's army had not completely surrounded the city.

Jan van Boendale's statement that William chased his mother from Zierikzee with his army remained unnoticed.

[22] Marcus Zuerius van Boxhorn noted the above safe conduct letter in the municipal archives of Zierikzee.

[33] In 1790 Hendrik van Wijn picked up De Jonge's find, and mentioned an August 1351 siege of Zierikzee, ending in a truce and the city submitting to William at the start of October.

Rijksarchivaris (Chief Archivist of the Dutch National Archives) Johannes Cornelis de Jonge (1793–1853), was a nephew of Marinus Jan, and a native of Zierikzee.

In his 'Verhandeling over den oorsprong der Hoeksche en Kabeljaauwsche twisten' he of course mentioned the siege, and the publication of the two charters by his uncle in 1778.