Where is your Hektor, Agamemnon, Achilles, or Paris? These are large Jupiter Trojans named after the heroes of the Trojan War in ancient Greece.
They are large asteroids following the orbit of Jupiter some 60 degrees before or after it (Lagrange points).
Jupiter has thousands of trojans over 1 kilometer wide, but only 18 or so that are over 100 miles wide. These 18 are divided into two groups, the Greek group (ahead of Jupiter) and the Trojan group (trailing Jupiter). Links to ephemeris tables for these two groups are provided below.
Not only Jupiter, but most of the other planets have trojans as well, although less numerous and smaller. Neptune has 28, Mars has 17, Uranus 2, Venus 1, and Earth itself has 2. More are likely to be found in the years ahead.
Trojans likely originated from some catastrophic event, such as the blowing up of a planet, between Mars and Jupiter. The incident left incredible debris, most of which became the main asteroid belt, but much of it, including the planet's moons, were captured by Jupiter, Mars, and some of the other planets.
While not as important as the planets themselves, trojans add to a planet's nature and history through important people and events. These "heroes" (or villains) and their personalities and accomplishments reverberate forever via the trojan bodies bearing their name. They also have an effect on your birth chart. Close aspects to planets or angles in your chart will reflect their influence.
Below are links to the Jupiter and Mars trojans as well as 1 from Earth.
Jupiter 2 group (Trojan camp)
Mars 1 largest trojans
Earth 1 trojan 2020XL5