Related Information for Celtus Celtus hail from Ireland.. Once known for their heavy rock music with Mama's Boys, the boys started Celtus after the death of their brother Tommy (youngest of the three and the drummer with Mama's Boys)..Pat & John McManus reverted back to their trad roots and came up with a haunting, eerie and very moving style of modern trad rock..Pat McManus can be spotted regularly playing all around Ireland.... read more