The Javanese pencak silat tradition were developed by several perguruan (schools). The notable school among others are Merpati Putih and Inti Ombak from Yogyakarta, and Perisai Diri from Surabaya. PPS Betako Merpati Putih stands for Perguruan Pencak Silat Beladiri Tangan Kosong Merpati Putih or "Empty Handed Pencak Silat Martial Art School of Merpati Putih". Officially established on 2 April 1963 in Yogyakarta, Merpati Putih is rooted in the Javanese beliefs and philosophies based on Javanese keraton (court) tradition, and can trace its origin to the martial art tradition of the 17th century Mataram Sultanate.[17] The name in Indonesian literary means "white dove". Although Merpati Putih literary means "white dove" in Indonesian language, and the bird become the symbol of the school, the name is actually an abbreviation of a Javanese proverb: Mersudi Patitising Tindak Pusakane Titising Hening which means "Always searching for the truth with inner peace". The school also has a motto: Sumbangsihku tak berharga, namun Keikhlasanku nyata, which means "My contribution is humble, but my sincerity is real".[18]