Astrolabe

The need to create a precise calendar for Muslim religious observances and pinpoint the direction of Mecca for prayers energized the fields of maths and astronomy. To measure the position of celestial bodies, Muslims perfected a Greek invention, the handheld Astrolabe. Author of a pioneering 9th-century treatise on algebra, Persian mathematical astronomer Al-Khawrizmi introduced Hindu numerals (and zero), which came to be called Arabic numerals. The word “algorithm” comes from his name.

P.S: Algorithms attracts one’s mind to focus on a problem delicately and deeply.