The Six Ages of the World, also rarely Seven Ages of the World, is a Christian historical periodization first written about by Augustine of Hippocirca AD 400. It is based upon Christian religious events, from the creation of Adam to the events of Revelation. The six ages of history, with each age lasting approximately 1,000 years, were widely believed and in use throughout the Middle Ages, and until the Enlightenment, the writing of history was mostly the filling out of all or some part of this outline. The outline accounts for Seven Ages, just as there are seven days of the week, with the Seventh Age being eternal rest after the Final Judgement and End Times, just as the seventh day of the week is reserved for rest. It was normally called the Six Ages of the World because in Augustine's schema they were the ages of the world, of history, while the Seventh Age was not of this world but, as Bede later elaborated, ran parallel to the six ages of the world. Augustine's presentation deliberately counters chiliastic and millennial ideas that the Seventh Age, World to Come, would come after the sixth.
Six Ages
The Six Ages, as formulated by Augustine of Hippo, are defined in De catechizandis rudibus, Chapter 22:
The First Age "is from the beginning of the human race, that is, from Adam, who was the first man that was made, down to Noah, who constructed the ark at the time of the flood", i.e. the Antediluvian period.
The Second Age "extends from that period on to Abraham, who was called the father indeed of all nations".
The Third Age "extends from Abraham on to David the king".
The Fourth Age is "from David on to that captivity whereby the people of God passed over into Babylonia".
The Fifth Age is "from that transmigration down to the advent of our Lord Jesus Christ"
The Sixth Age: "With His coming the sixth age has entered on its process."
The Ages reflect the seven days of creation, of which the last day is the rest of Sabbath, illustrating the human journey to find eternal rest with God, a common Christian narrative.
The idea that each age lasts 1000 years is based on II Peter 3:8: "But of this one thing be not ignorant, my beloved, that one day with the Lord is as a thousand years, and a thousand years as one day." The interpretation was taken to mean that mankind would live through six 1,000 year periods, with the seventh being eternity in heaven or according to the Nicene Creed, a World to Come. Medieval Christian scholars believed it was possible to determine the overall time of human history, starting with Adam, by counting forward how long each generation had lived up to the time of Jesus, based on the ages recorded in the Bible. While the exact age of the earth was a matter of biblical interpretive debate, it was generally agreed man was somewhere in the last and final thousand years, the Sixth Age, and the final Seventh Age could happen at any time. The world was seen as an old place, with more time in its past than its future. While Augustine was the first to write of the Six Ages, early Christians prior to Augustine found no end of evidence in the Jewish traditions of the Old Testament, and initially set the date for the End of the World at the year 500. Hippolytus said that the measurements of the Ark of the Covenant added up to five and one-half cubits, meaning five and a half thousand years. Since Jesus had been born in the "sixth hour", or halfway through a day, and since five kingdoms had already fallen according to Revelation, plus the half day of Jesus, it meant that five-thousand five-hundred years had already passed when Jesus was born and another 500 years would mark the end of the world. An alternative scheme had set the date to the year 202, but when this date passed without event, people expected the end in the year 500. By the 3rd century, Christians no longer widely believed the "End of the Ages" would occur in their lifetime, as was common among the earliest Christians.