Complex sentence: One of its churches dates from the 13th century; before the addition of a chancel in 1830, it church was only 25 feet long and 11 feet wide, and considered the smallest church in England.
Split into simpler sentences: One of its churches dates from the 13th century. Before the addition of a chancel in 1830, this church was 25 feet long and 11 feet wide, and considered the smallest church in England.