AK47s and tanks.
I would say catapults also cannons
castles, improved weapons and armour, farming techniques - better animal breeds, crop growing etc
Superior skill, organisation and weapons - and force of numbers. Don't forget that the Normans came in at the request of an Irishman - to help him get his kingdom in Leinster back, so it wasn't just "Normans - v - Irish", it was really a local quarrel in which one side hired foreign mercenaries, who then outstayed their welcome and got so powerful that Henry had to invade to slap them down again.
What food did The Normans grow?
what were the normans hobbies
Why did the Normans panic
Only one of them can be normans.
What did the Normans do after The Battle of Hastings?
the normestic annivercery when the Normans were discovered
the Normans wore chain-mail.
Normans Hall was created in 1921.
The Normans Went To Ireland in 1080