On 1 January 45 BC the Julian calendar took effect, introduced by Julius Caesar on the advice of the Alexandrian astronomer Sosigenes to replace the confused Roman lunar calendar, which had drifted by months. It has 365 days with an extra day every four years. To realign the seasons, the preceding year of 46 BC was stretched to 445 days, called the 'year of confusion'. The calendar spread with Roman rule and was used in Europe for 1,600 years, until the Gregorian reform of 1582 corrected its small error of 11 minutes a year. Russia and the Orthodox churches kept it much longer.
Before and after
- from 10 January 49 BCE to 17 March 45 BCECaesar's Civil War
- from 19 April 49 BCE to 6 September 49 BCESiege of Massilia
- 24 August 49 BCEBattle of the Bagradas River
- 46 BCEOrigins of Forum of Caesar
- 1 January 45 BCEThe Julian calendar takes effect
- 17 March 45 BCEBattle of Munda
- 44 BCEDiscovery of Caesar's Comet
- 15 March 44 BCEDeath of Julius Caesar
- 20 March 43 BCEBirth of Ovid
More in Science & technology
- 4th century BCEElements
- 287 BCEBirth of Archimedes
- c. 270s BCEAristarchus of Samos proposes that the Earth orbits the Sun
- 3rd century BCEArchimedes' principle
- c. 241 BCEEratosthenes measures the size of the Earth
- c. 131 BCEHipparchus discovers the precession of the equinoxes
The era
This moment belongs to the Ancient civilizations (3,200 BCE to 500 CE), writing, cities and empires. You can also browse everything in the 1st century BCE.