What did Achilles do?

Answer 1

He was one the Greek leaders who led an army in attacking Troy and the neighboring islands allied to Ilium. He did good at the start of the war but at one point he went beyond the attitude of being a good warrior by dragging the corpse of Hector who he fought and killed around the city. Enraged by his rudeness, Apollo punished him by guiding the arrow of Paris to his weak spot and killing him. Other accounts say that the arrow hit Achilles' heel, while other accounts say that it went straight to his heart.

Answer 2

He was a warrior in the Trojan War who had a supposedly invincible suit of armor. However, he wore no armor on his heel, so he got shot in the heel. Hence the expression"Achilles' heel".
The hero of Homer's Iliad, the son of Peleus and Thetis and slayer of Hector.