Complex sentence: Upon his return home, Smith was employed in the Church historian's office for a number of years, then as a clerk in the Endowment House, being in charge after the death of President Young, until it was closed.
Split into simpler sentences: Upon his return home, Smith was employed in the Church historian's office for a number of years. He also served as a clerk in the Endowment House, being in charge after the death of President Young, until it was closed.