The Muslim population of Chiang Mai is not particularly large - according to the 1980 census it comprised a mere 2.5% of the city's overall total - but it is successful, diverse, and (at least in the main Muslim neighbourhoods) very noticeable. Four main areas of Muslim settlement are readily identifiable by their mosques, halal restaurants, men sporting prayer caps and women wearing head veils. Two of these areas (Chang Pheuak and South Changklan) are predominantly Bengali, or South Asian in character, whilst two others (Baan Haw and Sanphakoi) are predominantly Yunnanese. Chiang Mai, sometimes written as 'Chiengmai' or 'Chiangmai', is the largest and most culturally significant city in northern Thailand, and is the capital of Chiang Mai Province. It is located 700 km (435 mi) north of Bangkok, among the highest mountains in the country. The city is on the Ping river, a major tributary of the Chao Phraya river. King Mengrai founded the city of Chiang Mai (meaning 'new city') in 1296, and it succeeded Chiang Rai as capital of the Lanna kingdom. The ruler was known as the Chao. The city was surrounded by a moat and a defensive wall, since nearby Burma was a constant threat. Chiang Mai formally became part of Siam in 1774 by an agreement with Chao Kavila, after the Thai King Taksin helped drive out the Burmese. Chiang Mai then slowly grew in cultural, trading and economic importance to its current status as the unofficial capital of northern Thailand, second in importance only to Bangkok.