Chronology in its function of dating past events has a venerable tradition stretching back into Greek antiquity, for instance in the marble tablet preserved in the Arundel Collection (Böckh 1843:2). But the chronology of the Christian era (with which we are concerned here) did not depend on classical sources, as was the case with so many of the sciences from astronomy to natural history. It was based on the Bible. Its main endeavour was to derive an authoritative dating for the creation of the world with respect to the birth of Christ. This was to be achieved by collating all the relevant references to be found in the testaments. However it proved impossible to achieve unanimity. The church historian Eusebios of Caesarea (c. AD 260-340) was probably the first to attempt this. In what has survived of his Chronikon (first published by J.J.Scaliger in the sixteenth century) he postulated the year 4000 BC for the creation of the world. In the fifth century an Egyptian monk Panodorus calculated a span of 5,493 years from

the creation to the birth of Christ. This was to form the basis of the Greek Orthodox calendar. In the seventeenth century the Jesuit priest Denis Pétau, also known as Petavius (1583-1652), reckoned 3,986 years (Petavius 1627, 1628, 1630). There were a number of others including the humanist Joseph Justus Scaliger (1540-1609), ‘the Hercules of Chronology’ (A.W.Schlegel 1821:90. XXIX, 27), mentioned above, the Irish Bishop James Usher (1581-1656) who estimated 5,000 years and Sir Isaac Newton (1643-1727). Most estimates came to about 4,000 years. The most recent one, adopted by the distinguished historian Johann Christoph Gatterer (1727-99) was 4,181 years (Gatterer 1785).