ab? h??tam muz?affar asfiz?r? (5th and 6th centuries a.h.), the great iranian mathematician, astronomers and scholors, was a contemporary of khayy?m. we don’t know much about his life excert what has been mentioned in some historians’ and scholars’, works. amony his most remarkable scientific achievements, we can mention his role in vernal equinox in order to modify and improve chronology and j...