This article brings together evidence from three disciplines to support a new and more detailed analysis of Chaucer's pentameter line. First, it draws upon linguistics, explaining the concepts and terms introduced by American scholars working in the field of generative metrics. Second, it embraces the use of statistical techniques in the analysis of poetic meter, first pioneered by Russian metrists. Third, it examines textual evidence from European literary history of how poets before Chaucer versified in France, Italy, and England. This combination of data suggests that Chaucer's pentameter owes more to the Italian endecasillabo than the French vers de dix, and confirms that Chaucer molded Middle English words and phrases to meet the iambic norm of the Modern English long-line canon.