Complex sentence: In 1935, he was invited to India to head a newly-opened all boys' boarding school, The Doon School, where he was the first headmaster from 1935 to 1948.
Split into simpler sentences: In 1935, he was invited to India to head a newly-opened all boys' school, The Doon School. In Doon, he served as the first headmaster from 1935 to 1948.