Complex sentence: The church was built between 1822 and 1824 and was known as first as the Camden Chapel, then, unofficially, as St Stephen's; it did not receive the dedication of All Saints until 1920.
Split into simpler sentences: The church was built between 1822 and 1824 and was known as first as the Camden Chapel, then, unofficially, as St Stephen's. It did not receive the dedication of All Saints until 1920.