Norse Mythology: Some books list Sataere as a Germanic god of agriculture and suggest that the name is another name for Loki. Guerbers' Myths of the Norsemen is one of these books, stating:
"Loki was confounded with Saturn, who had also been shorn of his divine attributes, and both were considered the prototypes of Satan. The last day of the week, which was held sacred to Loki, was known in the Norse as Laugardag, or wash-day, but in English it was changed to Saturday, and was said to owe its name not to Saturn but to Sataere, the thief in ambush, and the Teutonic god of agriculture, who is supposed to be merely another personification of Loki. "
Of course, Guerber does not provide us with a source. If we look at the Norse sources there are no references to Sataere or Saturn. Jan De Vries lists the Old English word Sataere as being derived from the word Saturn, thus not a separate diety, and it seems that Njord not Loki is the Norse god that more closely resembles Saturn. Could an association between Njord and Saturn be the cause of Scandinavians using Laugurdag -- bath or wash day -- in place of Saturday?
Grimm in his Teutonic Mythology reasons that Saturn was originally a Germanic deity and this is probably Guerber's source. Prof. E.G. Stanley in The Search for Anglo-Saxon Paganism states that Saturn is erroneously included among the gods of the Anglo-Saxons by some scholars (Grimm included) because of his appearence in an early Old English poem Solomon and Saturn. Moreover, Stanley relates the opinion of other scholars that the Saturn appearing in the poem represents the Chaldean god Saturn and not some Germanic deity.
(Nicole Cherry, A list of Norse Beings, http://www.ugcs.caltech.edu/~cherryne)