Today, the religion of Karo people are mostly Christian, a religion brought to Sumatra in the 19th Century by missionaries. However, an increasing number living away from the Karo Highlands have converted to Islam, with the influence of Muslim Malay from neighboring Deli area in Medan, and Javanese immigrants, thus making the traditional habits of pig farming and cooking less common. Some Muslims and Christians however still retain their traditional animist beliefs in ghosts, spirits (perbegu), and traditional jungle medicine, despite that fact it contradicts their other beliefs. The Gereja Batak Karo Protestan or Karo Batak Protestant Church is the largest church among the largely Christian Karo people of North Sumatra, Indonesia. This tribal congregation was established formally in 1941 as a Reformed-Calvinist church. The church has 276,000 members (as of 2006) in 398 congregations with 196 pastors.