- 312: Constantine the Great is victorious over Maxentius at the Battle of the Milvian Bridge; his victory resulted in his becoming Western Augustus, or ruler of the entire Western Roman Empire.
- 1839: The Greek government exiles clergyman-philosopher Theophilos Kairis.
- 1940: Prime Minister Ioannis Metaxas replied with the single-word reply "no", when Mussolini demanded occupation rights to strategic Greek sites. Greece officially entered World War II.
- 1944: German soldiers, while on retreat, sabotaged and destroyed the bridge of Papadia, and the tunnel and bridge of Brallos.
- 1955: Michalis Karaolis is arrested in Cyprus.
- 1959: The electricity plant of Ptolemaida begins its operations