[McSwiggins]

Fionn mac Cumhaill (transcribed as Finn MacCool) was a mythological hunter and warrior who was actually a real person. As a young boy he studied under a druid who was having Finn cook the salmon of knowledge for him. You've heard of the salmon of knowledge right? Rumor had it, if you ate it you gained all the knowledge in the world. Well, Finn was cooking it for his master but was instructed not to eat any himself. Finn accidentally burned his thumb on the Salmon and instinctively put it in his mouth like people will sometimes do to ease their initial pain. Well, since his thumb had touched the salmon of knowledge, when he put it in his mouth, he accidentally ingested some of the juices of the salmon. When his master saw he had gained knowledge by this, he let Finn eat the Salmon of Knowledge instead of himself, which comes into play in a few myths later in his life.
Finn was leader of the Fianna, a band of warriors sworn to protect the high king of Ireland with their lives.
He was out hunting and found a deer who was actually a woman under a spell. He brought her home and changed her into her true human form and they married and soon she was pregnant. But he had to go into battle with the Fianna for the high king, so he had to leave her alone. The sorcerer who had once turned her into a deer found her and took her, returning her form into a deer and releasing her in the wild. When Finn came home and realized what happened he was devastated. He searched for so long for her but never ended up finding her. He did find their son who was a fawn. He changed him back into a child named him Oisin and raised him carefully. Oisin also became a member of the Fianna once he became old enough.
In some myths Finn was a giant. One such myth is the Irish creation myth for Isle of Man. Finn was in a fierce battle with an enemy. Finn was known as the lands best and most skilled warrior on the battlefield. Well, the enemy he was fighting was his match. Finn was struggling and he was getting tired and quite frustrated. He picked up a huge chunk of the earth of Ireland (remember, he's a giant in this myth) and he threw it at his enemy but missed. It landed in the ocean between Ireland and England and became what is now Isle of man. There is a rock formation jetting out from the surface of the ocean about 200 miles off the coast of county Donegal (the most North western county in Ireland) called Rockall. It has a similar creation myth. Finn the giant was peacefully sitting on the beach overlooking the ocean. He picked up a rock and skipped it. Where it landed became known as what is now Rockall.