|Centuries:||1st century BC – 1st century – 2nd century|
|Decades:||20s BC 10s BC 0s BC – 0s – 10s 20s 30s|
|Years:||1 AD 2 AD 3 AD – 4 AD – 5 AD 6 AD 7 AD|
|4 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||757|
|Chinese calendar||癸亥年 (Water Pig)
2700 or 2640
— to —
甲子年 (Wood Rat)
2701 or 2641
|Coptic calendar||−280 – −279|
|Ethiopian calendar||−4 – −3|
|- Vikram Samvat||60–61|
|- Shaka Samvat||N/A|
|- Kali Yuga||3105–3106|
|Iranian calendar||618 BP – 617 BP|
|Islamic calendar||637 BH – 636 BH|
|Minguo calendar||1908 before ROC
|Seleucid era||315/316 AG|
|Thai solar calendar||546–547|
Year 4 (IV) was a common year starting on Wednesday or a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a leap year starting on Tuesday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Catus and Saturninus (or, less frequently, year 757 Ab urbe condita). The denomination 4 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 Caesar Augustus summons Tiberius to Rome, and names him his heir and future emperor. At the same time, Agrippa Postumus, the last son of Marcus Vipsanius Agrippa, is also adopted and named as Augustus' heir.
- Tiberius also adopts Germanicus as his own heir.
- Sextus Aelius Catus becomes consul.
- The Lex Aelia Sentia regulates the manumission of slaves.
- A pact of non-aggression and friendship is signed between the Roman Empire, represented by Tiberius, and the German tribe the Cherusci, represented by their King Segimer. Arminius and Flavus, sons of Segimer, are brought into the Roman army as leaders of the auxiliary troops.
- Julia the Elder returns from exile to live in Rhegium in disgrace.
- Augustus pardons Gnaeus Cornelius Cinna Magnus, along with Aemilia Lepida, the granddaughter of Marcus Aemilius Lepidus, for alleged involvement in a conspiracy against the emperor.
- Marcus Plautius Silvanus is appointed as proconsul of Asia.
- King Phraataces and Queen Musa of Parthia are overthrown and killed, the crown being offered to Orodes III of Parthia—the beginning of the interregnum.
- Emperor Ping of Han marries Empress Wang (Ping), daughter of Wang Mang, cementing his influence.
- Wang Mang is given the title "superior duke".
Arts and sciences
- Nicolaus of Damascus writes the 15-volume History of the World.
- Columella, Roman writer (d. 70)
- Daemusin of Goguryeo, King of Goguryeo (d. 44)
- Some believe that Jesus of Nazareth was actually born this year
- Gaius Caesar (b. 20 BCE), son of Marcus Vipsanius Agrippa and Julia the Elder, dies from wounds suffered during a campaign in Artagira, Armenia.
- Bak Hyeokgeose of Silla, first ruler of Korea (b. 69 BCE).
- Gaius Asinius Pollio, Roman orator, poet and historian (b. 65 BCE).[a]
- Terentia (b. 98 BCE), first wife of Marcus Tullius Cicero.
- Klingaman, William K. (1990). The First Century: Emperors, Gods and Everyman. Harper-Collins. ISBN 978-0785822561.
- Mommsen, Theodor (1996). Demandt, Alexander, ed. A History of Rome Under the Emperors. Routledge (UK). p. 107. ISBN 978-0415101134.