It is not sure if Ibn al-Athir was of Arab or Curdish ethnicity, but it is agreed that he was one of the main writers and biographers of the Crusades Era, and one of the Great Historians of the Muslim World.
He was born in the Great Seljuq Empire, modern Turkey, and experienced all the wars and chaos brought by Franks in the Crusades, living in Mosul, Baghdad and Damascus, even travelling with Saladin through for a period.
So, despite for being one of the only authors of its time to show respect and admiration for some of the Frank´s qualities, his main work "The Complete History" (Al-Kamil fi al-Tarikh"), that aims at telling his history of the world, has obvious bias in favour of the Muslim cause.
Which can be observed in his accounts of the death of the Christian ruler of Tyre, in a way that could not be written by modern historians:
"In this year, on 13 rabi II, the Frankish Marquis, the ruler of Tyre-- God [email protected] him!-- was killed. He was the greatest devil of all the Franks."