I'm a bit new to the Medieval era of history. In college my focus was primarily 19th ce American, so I have only what I learned in high school and the two classes in college that I took. I'm trying to build up a library of medieval history books however I have run into a few problems. On the one hand, most of the general histories in bookstores are popular histories without cited primary sources. On the other hand, most histories by academic professionals tend to be quite specific and require the reader to already have a general knowledge of the medieval era. I'm basically looking for academic, cited, general histories that cover the Viking Age, the Norman Conquest, and the Crusades. Does anyone have any recommendations?