. No later than the 2nd century, the Romans named Saturday diēs Sāturnī ("Saturn's Day") for the planet Saturn, which controlled the first hour of that day, according to Vettius Valens. The day's name was introduced into West Germanic languages and is recorded in the Low German languages such as Middle Low German satersdach, saterdach, Middle Dutch saterdag (Modern Dutch zaterdag), and Old English Sæternesdæġ, Sæterndæġ or Sæterdæ
Between the 1st and 3rd centuries AD, the Roman Empire gradually replaced the eight-day Roman nundinal cycle with the seven-day week. The astrological order of the days was explained by Vettius Valens and Dio Cassius (and Chaucer gave the same explanation in his Treatise on the Astrolabe). According to these authors, it was a principle of astrology that the heavenly bodies presided, in succession, over the hours of the day. The association of the weekdays with the respective deities is thus indirect, the days are named for the planets, which were in turn named for the deities.
The Germanic peoples adapted the system introduced by the Romans but glossed their indigenous gods over the Roman deities in a process known as interpretatio germanica. In the case of Saturday, however, the Roman name was borrowed directly by West Germanic peoples, apparently because none of the Germanic gods was considered to be a counterpart of the Roman god Saturn. Otherwise Old Norse and Old High German did not borrow the name of the Roman god (Icelandic laugardagur, German Samstag).
In astrology, Saturn is associated with Saturday, its planet's symbol .svg){kind=small}
, and the astrological signs Capricorn and Aquarius.
Saturday is named in honor of Saturn, the Roman god of agriculture. Each of the days of our week are named in honor of a god or object deemed worthy of veneration by the Anglo-Saxons. The sun and moon each get their due in Sunday (from the Old English sunnandæg, or literally "sun's day") and Monday ("moon's day").
