Complex sentence: At that time, William Ewart Donnelly, a missionary teacher from New Zealand, was principal of Toorak Boys School or the Suva Methodist Boys' School--renamed the Suva Methodist Primary School in the 1970s or 1980s.
Split into simpler sentences: At that time, a missionary teacher by the name of Mr William Ewart Donnelly was serving as principal of Toorak Boys School or the Suva Methodist Boys' School. It was later renamed the Suva Methodist Primary School in the 1970s or 1980s.