Medieval Christian monks who worked on calculating human history from Adam to the Last Judgment were called "Computists". These monks created schematic chronological tables, in which appeared packages of years whose numbers had deeper, symbolic meanings (like 7, 14, 30, 420 and so on). The Old Testament is full of those packages. For the time after the Resurrection they called their chronology ERA (i.e. turning round, "year"). Their chronological scheme looked something like this:

ERA 666 is taken as the center of theological history (because of Revelation 13:18). This number should be read "six-six-six"; it belongs with 369 (three-six-nine) and 963 (nine-six-three) in a group of symmetric numbers, the last two of which form the second level. The distance between them is, in each case, 297 years. A magical number, 297 is the product of the important prime number 11 and three to the third power (27). For computists, 297 was an expression of the Trinity.

Subtracting 297 from 369, we arrive at 72. Adding 297 to 963 we get 1260; these two figures, 72 and 1260, belong to a third level, and they are again equivalent from a symbolical point of view.

Used as historical "year dates", these figures appear absurd to us. To the computists, however, this magical dating system made sense. Six-six-six (666) was chosen as the date when the Antichrist appeared; 369 was taken for the beginning of the Church; 963 for the beginning of the "Roman Empire of German Nation". Seventy-two (72) indicated the destruction of the Temple, later the Passion of the Savior, who described himself as the Temple which was to be destroyed and rebuilt in three days. And 1260 equaled the final destruction, the Last Judgment that was to be expected, as laid down in Revelation. For the early computists, this last figure lay in the future.

Later, the Catholic Church created a new kind of chronology, the Incarnation Count, which began with the Birth of Christ, a system called Anno Domini (AD) that we still follow today. At a certain moment (difficult to recognize how long ago) the original start of the ERA chronology must have been linked with the date assumed for the Julian Calendar Reform, which, according to present-day notions, was fixed at 44 B.C.

From then on, therefore, all ERA dates had to be re-calculated: 666 ERA minus 44 BC yields AD 622, which is the present date for the Hegira (the beginning of Islam, year of the Antichrist) in our schoolbooks. According to the same rule, the first worldwide Council (Beginning of the Church) moved from 369 ERA to AD 325 (Council of Nicaea). The founding of the Germanic Empire moved from 963 ERA to AD 919 (first Reichstag, Diet).

The year 72 ERA also received a new value by subtracting 44: It became AD 28, the date for Christ's death according to Victorinus. Only 1260, the date of the Last Judgment that still lay in the future, remained unchanged. When the Last Judgment failed to happen, its date was postponed twice, once to 1290, then to 1335 (see Daniel 12: 11-12).

Another way of converting the numbers used the difference of 38 years between the Gothic ERA and the Catholic Anno Domini count: 963 ERA is 38 years away from 1001; this moved the Birth of Christ from a.u.c. 753 to 759 (i.e. 7 BC).

By using time packages of 297 years, a recognizable source of error was created. This error leads to historical dates that are frequently nearly three centuries out of sync with other dates believed nowadays. Taking a different path, the time reconstructor Heribert Illig arrived at a result that described the 297 years as having been added to the AD year-count only once. Unfortunately he does not explain how he found this package of years. His expression "according to the present state of my knowledge" (Illig 1994, p. 20; 1996, p. 18) sounds mystical. There are various different ways based on both Christian and Islamic computations that reveal this jump (see Topper 1999).

The determination of the beginning of the German Empire in AD 911 and of the two battles against the "Hungarians" in 933 and 955 followed this pattern of symbolic numbers - here above all the holy 11 - as did the fixing of Otto III to the years 999-1001, combining this event with millennarism. The Christianization of many states, from Iceland to Hungary, was attributed to those magical three years. Thus in the 15th century the year AD 1000 was elevated to being a landmark of European history. The imperial coronation of Charlemagne was also placed in a central position, in 800 or 801 AD. (These movements were also described by Landes, 1988.)

On the same time line the Conquest of Jerusalem by the Persians - a historiographical topos that by retro-projection in the Bible was attributed to Sanherib - was fixed at 614. Illig's idea that the two events (the "loss" of Jerusalem and the foundation of the German Empire 911) were in fact contemporary, (i.e. 614=911) is arbitrary; it fits the general pattern of chronology creation, no more.