The medieval period was a lab experiment in history writing. The historiographical legacy of classical antiquity had been rich, but the types and methodologies of history-writing developed between around 500 and 1500 CE were not only more vast, but also formative for how history was to be written in the West.
To the ancient canonical genres of history, universal history and biography, medieval historians added new types such as the universal (and local) annals, the chronicle (scholars have been debating the difference between the medieval history, chronicle and annals for over a century now), the urban history, the dynastic history, the institutional history. the illustrated history, the genealogical history, the national history, etc. The proliferation of historiographical species and subspecies during the medieval period is unquestionable. Now, methodologies varied, as did world-views as well as political, social and religious commitments, not to mention the tools available to historians, such as access to information, to other books and to other perspectives.
The curious thing about medieval history writing is that it belonged nowhere. There was no place for it in formal education. All the slots in the trivium and quadrivium of medieval study were taken, history was not taught in schools and no university offered history degrees, in the way they offered programmes in theology, philosophy, medicine or law. Despite being left out, history always kept a foot in the door. There is no shortage of historians at any point during the medieval period. Even for the so-called dark centuries of the early Middle Ages (the period before 800 CE), historians kept the flame of literacy, scholarship and knowledge alive. Though marginal, history was at the forefront of the events, but circumstances were such that the medieval chroniclers and historians worked independently from one another. The traditions of historical scholarship which emerged during the period were not due to these writers of history books meeting to discuss method or substance; instead, they were due to the silent growth of historical schools where one generation of writers had been the readers of the previous generations. This explains two typically medieval types of chronicling, which are the annals and the compilation, where one author expands on the work of another, keeping the book open and dust-free.