Many words or terms in the A Song of Roland timeline have different meanings then IOTL, and a glossary is of some use here.
Ascomanni: A term for Viking. It comes from Ashmen, and refers to the wooden ships of the Vikings. It was used IOTL in Germany.
Farakhshanite: The name for Muslim Corsairs that live in Provence. IOTL they were thrown out after attacking Cluny, but ITTL they are used as a tool by the Kings of Burgundy in their power struggles.
Peace and Truce of God
East Sea: The Baltic Sea
Formosa: North America, or at least part of it
Pannonia: The province of the WRE formed out of what was OTL Western Hungary.
Anabasii New army units formed by the ERE Alexander during the Persian Wars. The Anabasii are scouting units and are to act as the first line of attack and scouting of a Greek Army. They are made up primarily of light infantry and light horsemen, such as the Patzinaks.
Duke (Dux): The title of a commander of an Imperial Legion rather then a noble title as IOTL.
Franciscans: An elite force of axe-men (so named from the Francisca, a form of axe) formed in the middle of the 10th Century. They are modeled heavily on the OTL Jomsvikings.
Jarl: A term from Denmark that had spread through the Empire, used to signify a commander below a Duke in the Imperial Army or commander of a camp of Franciscans.
Shadow Knight See Stiletto
Primate: The supreme Ecclesiastical power below the Patriarch of the West. They are generally tied to either a Kingdom or Geographical area. For example, the Primate of Francia has ecclesiastical control over the Kingdom of Francia, but the Patriarch of Spain has ecclesiastical control over the not only the Kingdom of Gothica but the Imperial provinces of Toledo, Valencia, Badajoz, along with Leon and Santiago, and the Christians in the Emirate of Cordoba.
Comes: The title granted to a Graf/Bishop/institution that holds a seat in the Diet of a Kingdom.
Graf: Low level landowner, analogous to an OTL Count.
Palatine: A generic term for clerks/bureaucrats, as the Palatine retains their original OTL role ITTL.