Numerical digit
From India, the thriving trade between Islamic sultans and Africa carried the concept to Cairo. Arabic mathematicians extended the system to include decimal fractions, and Muḥammad ibn Mūsā al-Ḵwārizmī wrote an important work about it in the 9th  century. The modern Arabic numerals were introduced to Europe with the translation of this work in the 12th century in Spain and Leonardo of Pisa's "Liber Abaci" of 1201. In Europe, the complete Indian system with the zero was derived from the Arabs in the 12th century.
Old Arabic
Only three rather short inscriptions in the fully evolved Arabic script are known from the pre-Islamic period. They come from 6th century CE Syria, two from the southern region on the borders of Hawran, Jabal Usays (528 CE) and Harran (568 CE), and one from Zebed (512 CE), a town near Aleppo. They shed little light on the linguistic character of Arabic and are more interesting for the information they provide on the evolution of the Arabic script.