Complex sentence: Of a Unitarian background, he was born in Holywood, County Down, and grew up in that town where he was educated, first in the school of the Reverend McAlister and then at nearby Sullivan Upper School.
Split into simpler sentences: Of a Unitarian background, he was born and raised in Holywood, County Down. He attended the school of the Reverend McAlister and then at nearby Sullivan Upper School.