Forggus mac Cellaig
He was the son of Cellach mac Rogallaig ( died 705 ) , a previous king and brother of Domnall mac Cellaig ( died 728 ) . 
<triplet> Cellach mac Rogallaig <subj> Domnall mac Cellaig <obj> child <triplet> Domnall mac Cellaig <subj> Cellach mac Rogallaig <obj> father