The Ussher chronology is a 17th-century chronology of the history of the world formulated from a literal reading of the Old Testament by James Ussher, the Archbishop of Armagh and Primate of All Ireland. The chronology is sometimes associated with young Earth creationism, which holds that the universe was created only a few millennia ago by God as described in the first two chapters of the biblical book of Genesis. Ussher's work fell into disrepute in the 19th century.
Published in 1650, the full title of Ussher's work in Latin is Annales Veteris Testamenti, a prima mundi origine deducti, una cum rerum Asiaticarum et Aegyptiacarum chronico, a temporis historici principio usque ad Maccabaicorum initia producto ("Annals of the Old Testament, deduced from the first origins of the world, the chronicle of Asiatic and Egyptian matters together produced from the beginning of historical time up to the beginnings of Maccabees").
Ussher's work was his contribution to the long-running theological debate on the age of the Earth. This was a major concern of many Christian scholars over the centuries.
The chronology is sometimes called the UssherLightfoot chronology because John Lightfoot published a similar chronology in 1642–1644. This, however, is a misnomer, as the chronology is based on Ussher's work alone and not that of Lightfoot. Ussher deduced that the first day of creation was October 22, 4004 BC on the proleptic Julian calendar, near the autumnal equinox. Lightfoot similarly deduced that Creation began at nightfall near the autumnal equinox, but in the year 3929 BC.
Ussher's proposed date of 4004 BC differed little from other biblically based estimates, such as those of Jose ben Halafta (3761 BC), Bede (3952 BC), Ussher's near-contemporary Scaliger (3949 BC), Johannes Kepler (3992 BC) or Sir Isaac Newton (c. 4000 BC). Ussher was influenced by the same account as the apocryphal Book of Jasher, dating the worldwide flood to 2349 BC and the birth of Terah in 2127 BC. The date of 4000 BC as the creation of Adam was at least partially influenced by the widely held belief that the Earth was approximately 5600 years old (2000 from Adam to Abraham, 2000 from Abraham to the birth of Christ, and 1600 years from Christ to Ussher), corresponding to the six days of Creation, on the grounds that "one day is with the Lord as a thousand years, and a thousand years as one day" (). This tradition was believed to indicate that Jesus would return in AD 2000, more than six thousand years after 4004 BC. Modern proponents of this interpretation hold that the creation date 4004 BC could be inaccurate.
Ussher's methods
The chronologies of Ussher and other biblical scholars corresponded so closely because they used much the same method to calculate key events recorded in the Bible. Establishing the chronologies is complicated by the fact that the Bible was compiled by different authors over several centuries with lengthy chronological gaps, making it difficult to do a simple totaling of Biblical ages and dates. In his article on Ussher's calendar, James Barr has identified three distinct periods that Ussher and others had to tackle:
"Creation to Abraham's migration." This section is fairly easy to calculate, using the chronological data in Genesis 5 and 11, which gives an unbroken male lineage, with numbers of years, from the creation to Abraham being called out of Ur of the Chaldeans. Ussher used the chronology found in the Masoretic text instead of the alternative chronologies found in the Septuagint and Samaritan Pentateuch. Ussher fixed this period as 2082 years, from 4004 to 1922 BC. "Abraham's migration to Solomon's temple." Ussher wrote that the time from Abraham leaving Haran to the Exodus was 430 years (based on Abraham's descendants suffering a period of 400 years of persecution, commencing 30 years after Abraham left Haran) states that 480 years elapsed from the Exodus to the beginning of construction of Solomon's temple in the fourth year of Solomon's reign. Thus the temple foundations were laid 910 years after Abraham left Haran; these 910 years spanned from 1922 to 1012 BC. "Period of the temple laid to the Babylonian captivity." This period is the most difficult to calculate, due to repeated difficulties in correlating the regnal years of the kingdoms of Judah and Israel. The simple addition of the reigns of Judah's kings results in a total of 430 years, but by positing a few overlapping reigns, Ussher shortened this to 424 years: 1012 to 588 BC.