| Millennium: | 1st millennium |
|---|---|
| Centuries: | 1st century BC – 1st century – 2nd century |
| Decades: | 10s 20s 30s – 40s – 50s 60s 70s |
| Years: | 39 40 41 – 42 – 43 44 45 |
| 42 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 42 XLII |
| Ab urbe condita | 795 |
| Armenian calendar | N/A |
| Assyrian calendar | 4792 |
| Bahá'í calendar | -1802–-1801 |
| Bengali calendar | -551 |
| Berber calendar | 992 |
| English Regnal year | N/A |
| Buddhist calendar | 586 |
| Burmese calendar | -596 |
| Byzantine calendar | 5550–5551 |
| Chinese calendar | 辛丑年十一月廿一日 (2678/2738-11-21) — to —
壬寅年十二月初一日(2679/2739-12-1) |
| Coptic calendar | -242–-241 |
| Ethiopian calendar | 34–35 |
| Hebrew calendar | 3802–3803 |
| Hindu calendars | |
| - Vikram Samvat | 98–99 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 3143–3144 |
| Holocene calendar | 10042 |
| Iranian calendar | 580 BP – 579 BP |
| Islamic calendar | 598 BH – 597 BH |
| Japanese calendar | |
| Korean calendar | 2375 |
| Minguo calendar | 1870 before ROC 民前1870年 |
| Thai solar calendar | 585 |
Year 42 (XLII) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Caesar and Piso (or, less frequently, year 795 Ab urbe condita). The denomination 42 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.