The Jupiter trojans, frequently called trojan asteroids or just trojans, are a large group of asteroids that share the planets Jupiter's orbit around the sun. They are named for heroes in the ancient Greek tales of the Trojan War. In the Lagrangian Point, the gravity is such that another small object can tag along in orbit without being pulled in or pushed out.
As things aren't getting pushed out of there, they become stuck in there as well, which created large clumps of asteroids in Jupiter's orbit. (Trojan Asteroids). The group ahead of Jupiter is known as the Greek Camp, and the group behind it The Trojan Camp, with asteroids being named after famous people in that ancient war. Together, these two groups have as many asteroids as the asteroid belt.