was a common year starting on Friday
(link will display the full calendar) of the Julian calendar
Events of 1378
January - June
July - December
- Holy Roman Emperor Charles IV visits his nephew Charles V of France to publicly celebrate the friendship between their two nations.
- The Papacy makes a permanent move back from Avignon to Rome, ending the Avignon Papacy.
- France, Aragon, Castile and León, Cyprus, Burgundy, Savoy, Naples and Scotland choose to recognise Antipope Clement VII. Denmark, England, Flanders, the Holy Roman Empire, Hungary, northern Italy, Ireland, Norway, Poland and Sweden continue to recognise Pope Urban VI.
- Dmitri Donskoi of Moscow & Vladimir resists a small invasion by the Mongol Blue Horde.
- Tokhtamysh dethrones Timur Malik as Khan of the White Horde.
- Kara Osman establishes the Turkomans of the White Sheep dynasty at Diyarbakır in present-day southeast Turkey.
- The Turks capture the town of Ihtiman in west Bulgaria.
- Uskhal Khan succeeds his father, Biligtü Khan, as ruler of the Yuan Dynasty in Mongolia.
- Balša II succeeds his father, Durađ I, as ruler of Zeta (now Montenegro).
- Tai Bian succeeds Zhao Bing Fa as King of Mong Mao (now northern Myanmar).
- Da'ud Shah succeeds his assassinated nephew, Aladdin Mujahid Shah, as Bahmani Sultan in present-day southern India. Da'ud Shah is assassinated in the same year and is succeeded by Mohammed Shah II.
- Sa'im al-Dahr is hanged for blowing the nose off the Sphinx.