Sarekat Islam or Syarikat Islam (Islamic Association or Islamic Union, SI) was an Indonesian socio-political organization founded at the beginning of the 20th Century during the Dutch colonial era. Initially, SI served as a cooperative of Muslim Javanese batik traders to compete with the Chinese-Indonesian big traders. From there, SI rapidly evolved into a nationalist political organization that demanded self-governance against the Dutch colonial regime and gained wide popular support. SI was especially active during the 1910s and the early 1920s. By 1916, it claimed 80 branches with a total membership of around 350,000.