Military history of the Crusader states
The Seljuk–Crusader War began when the First Crusade wrested territory from the Seljuk Turks during the Siege of Nicaea in 1097 and lasted until 1128 when Zengi became atabeg of Aleppo. At the latter date, the chief threat to the Crusaders from the east and north became the Zengids. The conflict was generally fought between European Crusaders and the Seljuk Turks and their vassals. The Muslim Syrian emirates occasionally allied themselves with the Christians against rival states.
List of sources for the Crusades
Relevant eastern (Muslim) historiographies include works by Ali ibn al-Athir (d. 1233), 
Baha ad-Din ibn Shaddad (d. 1234), Abd al-Latif (d. 1231), Ibn Jubayr (d. 1217), Ibn Khallikan (d. 1282), Abu al-Feda (d. 1331).
Contemporary Muslim historiographers such as Ali ibn al-Athir refer to the Crusades as the "Frankish Wars" (). The term used in modern Arabic, "ḥamalāt ṣalībiyya", lit. "campaigns of the cross" is a loan translation of the term "crusade" as used in Western historiography. 
Later Muslim historiography did not focus on the Crusades as a single or coherent event. One main reason for this is that the Crusades in retrospect figure as more of a marginal issue compared to the final collapse of the Caliphate under the Mongol invasions and the eventual replacement of Arab rule by the Turkish Ottoman Empire, which suppressed Arab nationalism for the following seven centuries. The end of the "Islamic Golden Age" was thus only partially due to the Crusades, and more so to the Turkic and Mongol expansions. According to modern historians of Islamic history such as Murphy (1976) and Mansfield (2003), the collapse of the Caliphate led to the development of "intellectual barriers" and "isolationist policies" in the Muslim world.