Punjabi speakers in Pakistan use the Nastaliq variant of the Perso-Arabic script instead. Gurmukhi descends from the ancient Śāradā script, and took shape in the 1600s under the tutelage of the Sikh Gurus. Unusually for a Brahmic script, Gurmukhi has very restrictive character conjunct rules, as well as a relatively smaller character set. The script does not follow the Sanskritic model adhered to by most other Brahmic scripts, showing some influence from the Arabic script in its ordering and some character functions. The Gurmukhi tradition is closely linked to the Sikh faith, native to Punjab. The name Gurmukhi is a reference to the Gurus of Sikhism, the founders of the faith, who are also credited with popularising and propagating Gurmukhi. Sikh scripture was composed and is read in Gurmukhi.