What is "ewostatewos"

Ewosṭatewos ( ʾĒwōsṭātēwōs, also Yōsṭātēwōs, a version of Eustathios; July 15, 1273 – September 15, 1352 according to the Julian calendar) was an important religious leader of the Orthodox Tewahedo during the early period of the Solomonic dynasty of Ethiopia. He was a forceful advocate for the observation of the Sabbath in Christianity. His followers, known as the House of Ewostatewos (individuals are known as Ewostathians), have been a historic force in Tewahedo Orthodoxy.