Eris played a significant part in Greek mythology. One of the most important legends in which she is involved begins with a wedding - the wedding of Peleus and Thetis, to be precise. Apparently, someone forgot to invite the goddess of discord to the festivities. That was the first mistake in a long chain of disastrous events. For Eris simply showed up at the wedding anyway, with mayhem on her mind. When she arrived, the goddess tossed a golden apple into the crowd of famous faces. This tempting apple was tagged with the phrase "to the fairest".
So, the immediate question was, who deserved this irresistible piece of fruit? Should Aphrodite, the goddess of love and beauty, get the apple? Or should Hera, Queen of the Olympians, win it? Or perhaps Athena, the grey-eyed goddess of wisdom, should have the prize. As they were all beautiful goddesses, this was not an easy decision.
In order to avoid an ugly scene, a mortal named Paris was chosen to decide who should have the golden apple. Tempted by Aphrodite's offer of the most comely mortal woman, Paris awarded the prize to the goddess of love. Unfortunately, Helen (the loveliest woman) was already married. And from this seemingly minor event - an apple thrown at a wedding - the notorious Trojan War began. Eris obviously did her job of creating discord a little too well.
Discordia was the name the Romans called Eris.
Who's Who in Classical Mythology