However, a conflict soon arose between Margaret and her son William, as he refused to honor the terms in her abdication document by withholding the allowance she had demanded in turn for abdicating in his favor. Willem's opposition among the nobles of Holland asked Margaret to return to run Holland again, and in March 1350, Margaret had returned to Henegouwen, where she retracted her abdication in 1 June. The Cod League was formed on 23 May 1350 by a number of supporters of William, and on 5 September of the same year, the Hook League was formed in support of Margaret. Soon afterward these factions clashed and a civil war began, known as the Hook and Cod wars.