**Concise Curriculum Vitae**

**Jan Zuidhoek was born in
1938, studied mathematics, physics, and astronomy at the university of Utrecht
from 1960 to 1969, and was a teacher of mathematics from 1970 to 2001 at the
Gymnasium Celeanum in Zwolle. After having gone deeply into the fields of
history of mathematics, chronology, and history of early Christianity, he
became fascinated by the Alexandrian computus, i.e. the Alexandrian form of the
computus paschalis being the science developed from the beginning of the third
century on behalf of the determination of the date of Paschal Sunday. In 2009
he succeeded, by using NASA’s Six Millennium Catalog of Phases of the Moon, in
determining the initial year (AD 271) of De
ratione paschali, i.e. the medieval Latin text containing the legendary
19-year Paschal cycle of Anatolius, the famous third century Alexandrian
computist who invented the very first Metonic 19‑year lunar cycle. The
underlying reconstruction of the so called proto-Alexandrian 19‑year
lunar cycle was the subject of the presentation he gave at the international
conference on the science of computus which took place at the university of
Galway in 2010. This presentation resulted in his article entitled “The initial
year of De ratione paschali and the
relevance of its paschal dates”, which was published in 2017 in the proceedings
of that conference. The presentation he gave at a similar conference in 2018
led to this book, in which he describes not only his reconstruction of both
lost Alexandrian Metonic 19-year lunar cycles actively constructed already
before the first council of Nicaea (AD 325), turning point in the history of
Christianity, but also the development from the second of them to the
particular Metonic 19-year lunar cycle from which thirteen centuries later the
Italian astronomer Luigi Lilio and subsequently the German mathematician
Christoph Clavius would develop a modern, astronomically more correct, system
for determining the Gregorian calendar date of Easter Sunday.**

**© Jan
Zuidhoek 2019-2021**