Hasyim Asy'ari (Hāshim b. Ashʿarī) (1871-1947) was considered the most learned of the Javanese kiai (ʿulamāʾ) of his generation. He founded the Tebuireng pesantren in Jombang (East Java, Indonesia) and was the chief religious authority of the Nahdlatul Ulama (Nahḍat al-ʿUlamāʾ, NU) association, from its founding in 1926 until his death. Hasyim was born into a well-connected family of ʿulamāʾ in Gedang, Jombang, where his maternal grandfather ʿUthmān led a pesantren . His father, Ashʿarī, originally from Demak, in Central Java, was Kiai ʿUthmān's favourite student