Ariarathes IV Eusebes (220-c.163): king of Cappadocia.
- Son of Ariarathes III and Stratonice III
- Married to: Antiochis (daughter of Antiochus III the Great and Laodice III)
- Successor of: Ariarathes III
- 220: Accession
- 193: Marriage to Antiochis (daughter of the Seleucid king Antiochus III the Great and Laodice III)
- 192: Antiochus III attacks Greeks, beginning of the Syrian War
- Roman troops expel Antiochus from Greece and invade Asia
- 190: Battle of Magnesia: Antiochus defeated; Ariathes IV switches sides
- 188: Peace treaty between Roman and the Seleucid Empire; Cappadocia is accepted as a Roman ally and gains Tyana.
- Ariarathes' daughter Stratonice IV marries king Eumenes II of Pergamon, a Roman ally.
- 182: Rome supports Cappadocia in the Pontic War against king Pharnaces I of Pontus (182-179).
- 172: Rome requests military support against the Macedonian king Perseus (Third Macedonian War)
- 168 Rome victorious against Macedonia
- c.163: Natural death
Succeeded by: Ariarathes V Philopator