Gilles wrote two Latin chronicles, Chronicon majus and Chronicon minus, dealing with the history of the world, spanning from its creation up to 1349. This work, which was expanded by another writer to encompass 1352, is valuable for containing the history of northernFrance and Flanders in the first half of the 14th century. It is published by J. J. de Smet in the Corpus chronicorum Flandriae. Gilles also wrote some French poems, Poesies de Gilles Li Muisis, which have been published by Baron Kervyn de Lettenhove.