in Ancient Geography, the name of several towns, so called from their position among, or near, fens. The most important town of this name was in Laconia, at the mouth of the Eurotas, in a plain close to the sea, marshy yet very fertile. In the Dorian conquest of the Peloponnesus Helos was taken, and its inhabitants carried off to Sparta, and reduced to slavery. Their name is said to have been applied by their masters generally to all the bondsmen or helots that fell into their power. This, however, is a mere etymological fancy. (See Helot.) The name Helos is still given to the campaign country at the mouth of the Eurotas; and ruins, said to belong to the ancient town, are still visible near Bizani. Leake identifies Helos with Priniko; but as the remains there do not go further back than the middle ages, the first supposition is the more likely to be true.