, an important school of speculative theology within Twelver S̲h̲īʿism, influential mainly in Persia and ʿIrāḳ since the early 19th century. Although at times its leaders have been excommunicated and its doctrines condemned as heretical, S̲h̲ayk̲h̲ism (also known as the Kas̲h̲fiyya) has accommodated itself fairly successfully with the majority Uṣūlī establishment and is generally regarded as a school ( mad̲h̲hab ) rather than a sect ( firḳa ). Bābism [see bāb , bābīs ] began in the 1840s as a radical development of S̲h̲ayk̲h̲ī heterodoxy.

1. Early history.

The origins of S̲h̲ayk̲h̲…