a French poet of the sixteenth century associated with La Pleiade. While not a member of the Pléiade, he was known as a major influence on the literary life of his time, if not as a major poet. Guillaume would have known most if not all of those poets, and supported for them in their use of the French language in their poetry. While he too wrote in vernacular French (rather than Latin), he is known for championing the use of Old French in prose and poetry and was against replacing it with a more "manufactured" orthography.
