How do I get rid of CALENDAR notifications?

Every time I access my 635 phone I see a notification for The Battle of the Boyne! This offends me more than I can say. Some Irish sectarian excuse for ongoing bigotry dating back to 1690 - and it's ON MY PHONE! I want it away. Now.

The reason I imagine is that it seems to be a public holiday in Northern Ireland. Well, surely if I delete all public holidays in calendar settings, it would go away? No, it stays.

Surely if I remove the calendar from my home page, it would go away? No, still there.

Right now either I get rid of this notification somehow, or I get rid of the whole calendar app (how do I do that?) or I get rid of this phone altogether.

Can someone please help?