GODOT – Graph of Dated Objects and Texts

The aim of this graph database system is to create and maintain a gazetteer of calendar dates in different calendar systems, initially those used in Greek and Roman antiquity across the mediterranean area, and provide links to attestations of these dates in online editions. Like geographical gazetteers this authority list can be used to provide stable, unique identifiers (URIs) for each date in any of the calendar systems that has been used to refer to an astronomical day in any ancient source, whether literary texts, papyri, ostraca or inscriptions. It will serve as a means to search and browse ancient texts by their precise temporal footprint using these URIs in digital editions and databases or TEI/EpiDoc XML driven projects.

Currently there are some 5,800 dates in the database, based on more than 7,000 attestations, from a number of different ancient calendar and dating systems like:

Where a clear system of conversions between different calendar systems has been established, dates will be converted algorithmically into (proleptic) Julian calendar and Julian Day Numbers. As more and more dates from antiquity are linked to the GODOT infrastructure, a complex knowledge graph of ancient dated objects and texts evolves.

Setting up the initial database has been supported by the Andrew W. Mellon Foundation (July - December 2018). All data can be reused under the CC BY-SA 4.0 licence.


Started in September 2019, the GODOT blog publishes articles and posts about historical chronological data, usually in a non-Gregorian calendar system, in digital environments like databases, digital editions and websites.

GODOT Workshop: Non-Gregorian Calendar Dates in Digitial Humanities

The first GODOT workshop about non-Gregorian dates in digital environments took place in Heidelberg on 26. and 27. November 2018 at the Heidelberg Academy of Sciences and Humanities.