In the ancient Persia and in the different historic eras, languages such as “Ilami”, “Avestaaee”, “Pahlavi”, and “Farsi-e-Mianeh” were spoken. It is believed that ancient Persian script was invented by about 500-600 BC to provide monument inscriptions for the Achaemenid kings. These scripts consisted of horizontal, vertical, and diagonal nail-shaped letters and that is the reason in Persian it is called “Script of Nails” or “Khat-e-Mikhi”, or cuneiform as it is known in English.
Avestaaee script was written with a feather pen, usually on animal-skin pages. It is surprising that this script has similarities with Arabic scripts such as “Sols” and “Naskh” that centuries later were invented. However, unlike these scripts, letters in Avestaaee were not connected to each other to form a word but they just were written separately next to each other (similar to Latin scripts). However it wrote from right to left
After the attack of Arabs to Persia, Iranians were forced to learn study and write in arabic which is a language containing 28 alphabet letters and persians added 4 letters to it ("g","ch","p"."zh") and made the persian alphabet. Around one thousand years ago, Ibn Muqlah and his brother created six genres of Iranian calligraphy, namely "Tahqiq", "Reyhan", "Sols", "Naskh", "Toqi" and "Reqa". These genres were common for four centuries in Persia.
In the 14th century, "Mir Ali Tabrizi" combined two major scripts of his time i.e. Naskh and Taliq and created the most attractive Persian Calligraphy style, "Nas’taliq". In past 500 years Iranian calligraphy called Nastaʿlīq.is one of the main script styles used in writing the Perso-Arabic script, and traditionally the predominant style in Persian calligraphy.
What makes Nastaliq unique is that unlike its ancestors, Nastaliq follows natural curves. In other words, unlike Arabic scripts that follow logical/geometrical designs, Nastaliq follows the nature and natural curves. There are a lot of resemblances found between the curves used in Nastaliq and natural curves and that makes it harder to learn.