**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 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 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.**

**some more photographs (with thanks to Nico Assies, Dick Hollemans,
Sander Zuidhoek, Michiel van Sleen, Sander Zuidhoek, and Thom Snijders
respectively)**

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**about 1995 Leuvenum 2005 (with Marie)**

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**Bunnik 2004 (with Marie and Siem)**

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**Hilversum
2007 (with Fiene)**

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**Putten2006
(with Marie, Katja, and Fiene)**

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** ****Galway 2018 (with Immo Warntjes and
Daniel P. Mc Carthy)**

**© Jan
Zuidhoek 2019-2020**