About 1,000 Catholics and alumni gathered Saturday for a thanksgiving Mass to mark the founding of the Maryknoll Sisters 100 years ago. The special event also saw the official opening of the Maryknoll Convent School’s new Heritage Centre. The center will house relics of the school and the convent. Founded in the United States in 1912, the first group of six Maryknoll Sisters arrived in Hong Kong in 1921 as part of the congregation’s first mission overseas. Besides school and parish work, the sisters in the China region today serve domestic helpers and the deaf in Hong Kong and Macau.