The change from “Joliet” to “Jolliet” is based first on the constant custom of French writers, both in the Old World and the New. Pierre Margry, the great French archivist, the most learned man of his time concerning New France documents, always speaks of Jolliet. Félix Martin of the Jesuit order, who wrote in 1861, uses Jolliet. Father Tailhan, the learned editor of Perrot’s _Memoire_, uses Jolliet. The same is true of John G. Shea, Henri Harrisse, Abbé Ferland, and Jolliet’s latest biographer, Ernest Gagnon, who in 1902 published a life of Jolliet derived from many newly discovered and hitherto unpublished manuscripts. All these authors were familiar with the seventeenth-century documents in the original form. They decided that “Jolliet” was used more often and more consistently than any other form, though all of them would admit that in many documents the spelling “Joliet” may be found. For example, the baptismal register[66] spells the name by which Jolliet was christened, “Joliet.” While still a boy in the convent at Quebec he was known as young Joliet.[67] After Jolliet entered active life the name was usually spelled with two “l’s.” His earliest voyage is reported by the Sulpician, Galinée, who met him in 1669 at the head of Lake Erie and calls him “le sieur Jolliet.”[68] In 1671 he took part in the pageant of Sault Ste. Marie, when he was again spoken of as “le sieur Jolliet.”[69] Father Claude Dablon, who first reported the voyage of 1673, says, August 1, 1674, “le sieur Jolliet” has come back from the West.[70] Count de Frontenac, the governor-general of New France, in his first mention of the voyager, speaks of him as “Joliet”;[71] but thereafter in reporting his voyage and mentioning his maps he always writes the name “Jolliet.”[72] Several unsigned documents of the same period refer to him as “Jolliet.”[73] In 1677 a concession in Illinois was refused to “le sieur Jolliet.”[74] In 1680 a concession of the island of Anticosti was made to “Jolliet.”[75] Many more similar documents could be cited showing that the prevalent use in the seventeenth century was the form “Jolliet.” Lastly, how did the man himself write his name? A map published in Dr. R. G. Thwaites’s _Jesuit Relations_,[76] gives in the cartouche a letter signed “Joliet.” This has usually been supposed to be the explorer’s writing. A glance, however, at two authentic signatures will convince that he never wrote the name on the map. The first signature is from a tracing secured by Henry Legler for an article in the Wisconsin Historical Society _Proceedings_, 1905, page 169. The second is the signature to the marriage contract of which a facsimile is given in Gagnon, page 122. A glance will show that these two names were written by the same hand, and both are spelled “Jolliet.”