Mare Erythraeum is a very large dark dusky region of Mars that can be viewed by even a small telescope. Its name comes from the Latin for the Erythraean Sea because it was originally thought to be a large sea of liquid water. It was included in Percival Lowell's 1895 map of Mars.[1]
Under the name of De La Rue Ocean it was included in Procter's 1905 map of Mars.