Demetrius III Eucaerus: name of a Seleucid king, ruled from 97/96 to 88/87.
Successor of: Seleucus VI Epiphanes Nicator
- After 114/113, the Seleucid dynasty was divided into two branches, a northern one and a southern one.
- 97/96: The Egyptian king-in-exile Ptolemy IX Soter Lathyros makes Demetrius III Eucaerus and his (presumed twin) brother Philip I Philadelphus rulers in Damascus; they are successful in their war against Antiochus IX Cyzicenus and his son Antiochus X Eusebes Philopator.
- Summer 96: death of Antiochus VIII Grypus; he is succeeded by Seleucus VI
- Early 95: Seleucus defeats and kills Antiochus IX Cyzicenus, who is succeeded by his son Antiochus X Eusebes Philopator.
- In the deep south, Demetrius and Philip seem to have expanded their power: from now on, coins are minted for Philip, who seems to have resided in Beroea (modern Aleppo)
- Summer 94: Antiochus X defeats Seleucus VI. Leadership of the northern branch is transferred to Seleucus' brother Antiochus XI Epiphanes Philadelphus
- 93: Antiochus XI in Antioch; his reign, however, comes to an end, and Antiochus X takes over power in both Antioch and the north; Demetrius III and Philip I remain in the south
- Demetrius intervenes in the Hasmonaean kingdom, against king Alexander Jannaeus.
- c.89: Parthian invasion; end of the reign of Antiochus X, who is defeated by the Parthian leader Mithridates Sinaces and his ally Aziz the Arab
- Demetrius breaks off his war against Alexander Jannaeus and captures Antioch
- Demetrius and his twin brother Philip start to quarrel; Demetrius besieges Aleppo; Philip invites the Parthian king Mithradates III to help him
- 88/87: Demetrius is captured by the Parthians) and dies in captivity.
Succeeded by: his younger brother Antiochus XII Dionysus
- O. Hoover, "Revised Chronology for the Late Seleucids at Antioch (121/0-64 BC)" in: Historia 65/3 (2007) 280-301