The Lost Dowry is the fourth side quest in Greece (Act I), given by Theages in Laconia Hills. He will tell you, that demons smashed his cart and stole a golden necklace, which was the dowry for the man's daughter's wedding.
These demons are Eurynomus and can be found lurking in a cave a bit to the north-east. On the second level of the cave you'll find a larger red Eurynomus named Pandarus ~ Thieving Eurynomus - it holds the dowry necklace, a quest item. (Pandarus ~ Thieving Eurynomus can be killed again for another dowry necklace, however it cannot be sold or worn and so is useless to do so after having completed the quest)
Return the necklace to Theages to get your reward.
Reward: 400 Experience, random Relic Shard