Sneak Peak - Calendars Throughout History

Earlier today, I decided to visit a few classes that I’ve been hearing good things about from students. Everything that I had been told was absolutely true. I enjoyed all of them and will definitely be returning. The class I’d like to tell you a little bit about right now is Michael Goldweber’s “Calendars Throughout History.” The course focuses on understanding different calendar systems, from ancient to modern times, as well as the underlying mathematical and cultural assumptions embodied by each calendar system.

Mikey is an associate professor in the department of Mathematics and Computer Science at Xavier University in Cincinnati, OH. He attended Boston University receiving both a B.A. in Mathematics and a B.S.B.A. in Finance. Following this, and a short stint working in industry, he spent a year living in Israel. Upon returning from Israel he received both a Masters and a Ph.D. in Computer Science from Dartmouth College. A respected and active participant in the computer science education community, Mikey's current research focus is in systems virtualization.

“Calendars” meets every other morning at 8:00am – if a college student raves about an 8:00am class, you know it must be good. Today’s lecture and student presentations traced the development of the calendars of the Greeks and Babylonians as well as compared the two.


Both operated on a lunar system. The Babylonians had developed the beginnings of their calendar system by about 4,000 BC. However, their calendar only contained 354 days per year. Originally, the leaders would add a new month when necessary but by roughly 500 BC, the Babylonians had developed an algorithm that would add in the extra lunar cycles when needed over a 19 year cycle.


This type of system was proposed in the Greek system in 432 BC by Meton. However, it was rejected for a number of reasons, including the fact that it would interfere with the presence that the Olympic games held in the calendar. Instead, the Greeks chose an 8-year cycle where a new month as added in three times during that period. Eventually, Seleucus, a successor of Alexander the Great who came to power in 312 BC adopted the Babylonian system.

One important component of all of this that Mikey talked about, which is integral to our academic theme here at SAS, is migrations. The spread of ideas, culture, and knowledge was an integral factor in the establishment of these calendar systems, which can still be seen today. For example, the calendar developed and still used in Judaism is the same format as the Babylonian one, and even has a few months that are almost identical in name. Some scholars contend that it was adopted by the Jews during their exile in Babylon following the destruction of the First Temple. Even the idea of a Sabbath or day of rest, which can be found in Judaism, Christianity, and Islam can find its roots in the ancient Babylonian calendar, where the 7th, 14th, 21st, and 28th days of the month were identified as unlucky and as days not to work. This theme of migrations – of knowledge, people, and culture is something that will be reappearing in many courses and is something that students will also be tracing when they are in the field.