In Southeast Asia, the first true writing systems of pre-modern Austronesian cultures were all derived from the Grantha and Pallava Brahmic scripts, all of which are abugidas from South India. Various forms of abugidas spread throughout Austronesian cultures in Southeast Asia as kingdoms became Indianized through early maritime trading. The oldest use of abugida scripts in Austronesian cultures are 4th century stone inscriptions written in Cham script from Vietnam. There are numerous other Brahmic-derived writing systems among Southeast Asian Austronesians, usually specific to a certain ethnic group. Notable examples include Balinese, Batak, Baybayin, Buhid, Hanunó'o, Javanese, Kulitan, Lontara, Old Kawi, Rejang, Rencong, Sundanese, and Tagbanwa. They vary from having letters with rounded shapes to letters with sharp cuneiform-like angles; a result of the difference in writing mediums, with the former being ideal for writing on soft leaves and the latter ideal for writing on bamboo panels. The use of the scripts ranged from mundane records to encoding esoteric knowledge on magico-religious rituals and folk medicine.