I spent some of the weekend working out where I should start on the Stupor Mundi project. My conclusion is that I should concentrate on the most important sources first. In the past I think I made the mistake of starting outward and working in, so trying to build up a complete understanding of the period by reading secondary and primary texts connected with the period but not directly on the subject of the novel. I’ve decided to deal with my primary sources first and then read elsewhere if needed.
So my first priority is the biography of Piero della Vigna by Huillard-Breholles. This is in French so my first job is to translate it.
After that I want to look at the poems attributable to Piero and the other poets of the Sicilian School, I think this will provide a good indication of how they thought. My current reading points to more sophistication in some of them than one might think for that period.
Following on from that are things like the Constitutions of Melfi, the letters written by Piero not covered in Huillard-Breholles, the hunting treatise of Frederick, and then probably the biography by Kantorowicz, especially as he and his descendent are characters in the book.
I would recommend only seinndg what you consider to be a polished manuscript otherwise the chances of rejection will be much higher. If a story is rough around the edges then it won’t be published in Alt Hist. If you feel a story needs improvement I would recommend spending more time on it. However, if I do accept your story there may still be some changes to that are required.