I don’t think he did it on purpose, but Emperor Charlemagne left an amazing set of manorial instructions that will help my persona building a LOT. The document is called the Capitulare de Villis and dates from the 8th century in southern France. Either Charlemagne or his son Louis might have commissioned the document, which sets forth a series of orders for managing royal estates.
My persona is a large land holder but not exactly an Empress, so I’ve toned down the document to suit her circumstances. But I’m finding it invaluable for creating the farms and manors that “I” own. (I wish!) The online site is owned by the University of Leicester, the translation is by H.R. Loyn and J. Percival and you can find the linked text and more information here.