Achilles sent his beloved Patroclus into the fray dressed in his armor. The Trojans saw Achilles' insignia and assumed Patroclus was Achilles, which made him a focal point. Not being anywhere near the warrior that Achilles was, Patroclus died, killed in part by the leading warrior of the Trojans, the heir-apparent, Prince Hector.
Achilles' reaction was rage mixed with profound grief, but it was enough to shake him out of his indifference and rejoin the battle. He fought one-on-one against Hector until Hector died. Then Achilles attached him to his chariot and dragged him through the sand and dirt until he had reduced his rage. King Priam, father of Hector, went to Achilles to beg for the return of the mangled corpse of his son. Achilles was persuaded to do so in order that Hector might receive proper burial; however, as far as the mangling goes, the gods had prevented Achilles' actions from being effective. They had kept the corpse of Hector intact.
