Burmese folk religion refers to the animistic and polytheistic religious worship of nats (deities of local and Hindu origin) and ancestors in Myanmar (Burma). Although the beliefs of nats differ across different regions and villages in Burma, there are a handful of beliefs that are universal in Burmese folk religion. A nat is a god-like spirit. There are two main types of nats: nat sein (နတ်စိမ်း), which are humans who were deified after their deaths, and all the other nats which are spirits of nature (spirits of water, trees, etc). Nats are usually venerated in shrines called nat kun (နတ်ကွန်း) or nat sin (နတ်စင်). They can be placed anywhere to honor nature spirits (spirit houses) or they may be specialized shrines for particular nats. A village will traditionally also have a spirit which is their local patron; this is called a Bo Bo Gyi. The precise origins of Burmese folk faith and nat worship are not definitively known. However, at the time King Anawrahta (1044-1077) was ruling, nat worship was rampant. He became frustrated with this widespread worship of nats, and tried to eliminate them. The people continued to worship the nats, and so the king ordered the destruction of all statues and images of nats. Despite this people still worshipped them, by using a coconut as a symbol for them. Now in place of a typical nat statue, there sat a coconut, which served as an offering to the nat, as well as a symbol for the nat itself. The king came to the realisation that he could not possibly stop these nats from being worshipped, so he created a formal list of 37, strategically renaming the head one, Thagyamin, which was a name of Buddhist origin. He also placed statues of deva in front of the nats. This symbolised the preference for practising Buddhism over folk faith. Despite continued opposition, this nat worship survived. A testament to the continued survival of Burmese folk religion can be seen by the fact that the prime minister of Burma in the mid 20th century, U Nu, erected a nat-sin (nat shrine) as well as a traditional Buddhist shrine.