Arabic numerals
The first mentions of the numerals in the West are found in the "Codex Vigilanus" of 976.
Muhammad ibn Musa al-Khwarizmi
"On the Calculation with Hindu Numerals" written about 820, was principally responsible for spreading the Hindu–Arabic numeral system throughout the Middle East and Europe. It was translated into Latin as "Algoritmi de numero Indorum". Al-Khwārizmī, rendered as (Latin) "Algoritmi", led to the term "algorithm".