Complex sentence: The Quiggin family had been making confectionery since 1840 in the Isle of Man and when one of the four sons moved to Kendal in 1880, the mint cake company was formed.
Split into simpler sentences: The Quiggin family has been making confectionery since 1840 in the Isle of Man. When one of the four sons moved to Kendal in 1880, the mint cake company was formed.