|301 by topic|
|Ab urbe condita||1054|
|Chinese calendar||庚申年 (Metal Monkey)
2997 or 2937
— to —
辛酉年 (Metal Rooster)
2998 or 2938
|- Vikram Samvat||357–358|
|- Shaka Samvat||222–223|
|- Kali Yuga||3401–3402|
|Iranian calendar||321 BP – 320 BP|
|Islamic calendar||331 BH – 330 BH|
|Minguo calendar||1611 before ROC
|Seleucid era||612/613 AG|
|Thai solar calendar||843–844|
|Wikimedia Commons has media related to 301.|
Year 301 (CCCI) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Postumius and Nepotianus (or, less frequently, year 1054 Ab urbe condita). The denomination 301 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
- Emperor Diocletian issues his Edict on Maximum Prices, which, rather than halting rampant inflation and stabilizing the economy, adds to inflationary pressures by flooding the economy with new coinage and by setting price limits too low.
- Diocletian begins the construction of new roads in the Roman Empire. The Strata Diocletiana is built and lined with a series of forts (quadriburgia); it runs from the Gulf of Aqaba (Arabia) to the Euphrates.
- King Tiridates III proclaims Christianity as the official state religion. Armenia becomes the first nation to adopt Christianity.  Construction of the original Etchmiadzin Cathedral by Gregory the Illuminator begins.
- King Narseh of Persia abdicates, in favor of his son, Hormizd II.
- Sima Lun briefly usurps the Jin Dynasty.
- It was the first nation to adopt Christianity as its official religion. The Journal of Ecclesiastical History – Page 268 by Cambridge University Press, Gale Group, C.W. Dugmore
- The Armenian Massacres, 1894–1896: 1894–1896 : U.S. media testimony – Page 131 by A. Dzh. (Arman Dzhonovich) Kirakosian
- The Antiquities of the Christian Church – Page 466 by Johann Christian Wilhelm Augusti, Georg Friedrich Heinrich Rheinwald, Carl Christian Friedrich Siegel