What accounts for the emergence of the medieval parliament? What were its main functions? Whose interests did parliament serve and how powerful were the Commons? These are straightforward questions, but historians have been debating the answers for well over a hundred years, since Archbishop William Stubbs published his Constitutional History in 1875. This discussion surveys the main contributions to this discussion, tracing the rise and fall, and rise again, of the historiography of medieval parliaments. More recent work has demonstrated that the antecedents of parliamentary assemblies can be traced back to before the Conquest, but the focus of this discussion lies in the later medieval period and, particularly, the late 13th and 14th centuries, the period which has attracted most attention and discussion in modern scholarship.