Saturday

Saturday is the day of the week following Friday and preceding Sunday. Saturday is the second-to-last (sixth) day of the week according to ISO 8601 (see below). The Romans named Saturday Sāturni diēs ("Saturn's Day") no later than the 2nd century 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 sater(s)dach, Middle Dutch saterdag (Modern Dutch zaterdag) and Old English Sætern(es)dæġ and Sæterdæġ. However, the name was selected as a calque of the god Saturn, after whom the planet was named. The day was also referred to as "Sæternes dæġe" in an Old English translation of Bede's Ecclesiastical History of the English People. In Old English, Saturday was also known as sunnanæfen ("sun" + "eve" cf. dialectal German Sonnabend).

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.

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