| Millennium: | 1st millennium |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| 399 by topic |
|---|
| Leaders |
| Categories |
| Gregorian calendar | 399 CCCXCIX |
| Ab urbe condita | 1152 |
| Assyrian calendar | 5149 |
| Balinese saka calendar | 320–321 |
| Bengali calendar | −194 |
| Berber calendar | 1349 |
| Buddhist calendar | 943 |
| Burmese calendar | −239 |
| Byzantine calendar | 5907–5908 |
| Chinese calendar | 戊戌年 (Earth Dog) 3096 or 2889 — to — 己亥年 (Earth Pig) 3097 or 2890 |
| Coptic calendar | 115–116 |
| Discordian calendar | 1565 |
| Ethiopian calendar | 391–392 |
| Hebrew calendar | 4159–4160 |
| Hindu calendars | |
| - Vikram Samvat | 455–456 |
| - Shaka Samvat | 320–321 |
| - Kali Yuga | 3499–3500 |
| Holocene calendar | 10399 |
| Iranian calendar | 223 BP – 222 BP |
| Islamic calendar | 230 BH – 229 BH |
| Javanese calendar | 282–283 |
| Julian calendar | 399 CCCXCIX |
| Korean calendar | 2732 |
| Minguo calendar | 1513 before ROC 民前1513年 |
| Nanakshahi calendar | −1069 |
| Seleucid era | 710/711 AG |
| Thai solar calendar | 941–942 |
| Tibetan calendar | 阳土狗年 (male Earth-Dog) 525 or 144 or −628 — to — 阴土猪年 (female Earth-Pig) 526 or 145 or −627 |
Year 399 (CCCXCIX) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Eutropius and Theodorus (or, less frequently, year 1152 Ab urbe condita). The denomination 399 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.