Kufic is the oldest calligraphic form of which script?

Kufic is the oldest calligraphic form of the various Arabic scripts and consists of a modified form of the old Nabataean script. Kufic developed around the end of the 7th century in Kufa, Iraq, from which it takes its name, and other centres.

The Qur'an was first written in a plain, slanted, and uniform script but, when its content was formalized, a script that denoted authority emerged.

Until about the 11th century it was the main script used to copy the Qur'an. Professional copyists employed a particular form of Kufic for reproducing the earliest surviving copies of the Qur'an, which were written on parchment and date from the 8th to 10th centuries.