The island has been a center of Buddhist scholarship and practice since the introduction of Buddhism in the third century BCE producing eminent scholars such as Buddhaghosa and preserving the vast Pāli Canon. Throughout most of its history, Sri Lankan kings have played a major role in the maintenance and revival of the Buddhist institutions of the island. During the 19th century, a modern Buddhist revival took place on the island which promoted Buddhist education. Due to the islands close ties with India, Sinhalese Buddhism has been in part influenced by Hinduism and indigenous beliefs, and some Buddhists share similar beliefs with Hindus, such as the worship of Hindu deities, the caste system, and Animism. Some traditional Sinhalese Temple layout also includes individual shrines dedicated to Hindu gods. Some of the most important Hindu god’s worshiped by some Sinhalese Buddhists include Vishnu, Murugan, Pathini, Nata, Gambara, Dedimunda, Saraswati, Ganesh, Lakshmi, Shiva and Kali, etc. Demons and spirits are also invoked during Exorcisms and rituals, which seem to be customs passed down from Pre-Buddhist indigenous times. In 2007, there were around 6,000 Buddhist monasteries on Sri Lanka with approximately 30,000 monks.