Hi, fellow historical novels reader!
If you enjoyed the literary quality of The name of the rose you might find interesting "Baudolino" a 2000 novel by Umberto Eco about the adventures of a young man named Baudolino in the known and mythical Christian world of the 12th century.
Of the same historical period, you can consider the founder of historical novel as a genre, the great Sir Walter Scott in his novels of Scottish history such as Waverley (1814) and Rob Roy (1818). His Ivanhoe (1820) gains credit for renewing interest in the Middle Ages. In my modest opinion it is still a pretty good reading.
If you like action and suspense, than you can resort to The Pillars of the Earth, a historical novel by Ken Follett published in 1989 about the building of a cathedral in a fictional location in England, in the middle of the 12th century. Follet established himself as an excellent writers of thrillers. It shows.
A great bestseller that has chapters on that period and makes a very good reading is Poland by James A. Michener (1983). The chapters are:
From the East: Invasion by Tartars in the years 1240 to 1241. This chapter tells the story of the historic Mongol invasion of Poland and the Siege of Kraków and the Battle of Legnica.
From the West: Occupation by the Teutonic Knights in the late fourteenth century.
If you are ready to go back in time and enjoy one of the best story teller ever, read "I, Claudius" by Robert Graves, set in Roman times at the beginning of the Empire.
If you endure coming closer to modern time do try the first one of the enormously successful Angelique series. Angélique, the Marquise of the Angels is a 1956 novel by Anne Golon & Serge Golon, the first novel in Angélique series. Inspired by the life of Suzanne de Rougé du Plessis-Bellière, known as the Marquise du Plessis-Bellière.