Heliocles (Greek: Ἡλιοκλῆς; reigned 145–130 BCE) was a Greco-Bactrian king, relative (son or brother) and successor of Eucratides the Great, and probably the last Greek king to reign over the Bactrian country. His reign was a troubled one; according to Roman historian Justin, Eucratides was murdered by his son and co-ruler, though Justin fails to name the perpetrator. The patricide might have led to instability, even civil war, which caused the Indian parts of the empire to be lost to Indo-Greek king Menander I.
From 130 BCE a nomadic people, the Yuezhi, started to invade Bactria from the north and we could assume that Heliocles was killed in battle during this invasion. Details from Chinese sources seem to indicate that the nomad invasion did not end civilisation in Bactria entirely. Hellenised cities continued to exist for some time, and the well-organised agricultural systems were not demolished.
Even if this was the end of the original Greco-Bactrian kingdom, the Greeks continued to rule in northwestern India to the end of the 1st century BCE, under the Indo-Greek Kingdom. It is unclear whether the dynasty of Eucratides was extinguished with the death of Heliocles I or if members of the family emigrated eastwards. Several later Indo-Greek king, including Heliocles II, struck coins which could be associated with the dynasty.
- The Shape of Ancient Thought. Comparative studies in Greek and Indian Philosophies by Thomas McEvilley (Allworth Press and the School of Visual Arts, 2002) ISBN 1-58115-203-5
- Buddhism in Central Asia by B. N. Puri (Motilal Banarsidass Pub, January 1, 2000) ISBN 81-208-0372-8
- The Greeks in Bactria and India, W. W. Tarn, Cambridge University Press.
- Coins of Heliocles
- More coins of Heliocles
- Catalogue of the Coins of Heliocles I and Scythian Imitations
| Preceded by:
| Greco-Bactrian Ruler
| Succeeded by:|
| Dynastic lineage||Bactrian domain||Expansion into India|
|280 BCE||Foundation of the Hellenistic city of Ai-Khanoum in Bactria (280 BCE)|
|255 BCE||Independence of the Greco-Bactrian Kingdom from the Seleucid Empire (255 BCE)|
|255–239 BCE||House of Diodotus.||Diodotus I|
|239–223 BCE||Diodotus II|
|230–200 BCE||House of Euthydemus.||Euthydemus I|
|200–180 BCE||Demetrius I||Pantaleon|
|180 BCE||Euthydemus II||Agathokles|
|180–170 BCE||Antimachus I||Apollodotus I|
|170–145 BCE||House of Eucratides||Eucratides||Demetrius II|
|145 BCE||(Destruction of Ai-Khanoum by the Yuezhi in 145 BCE)||(Succession of|
|145–140 BCE||Plato Eucratides II||Indo-Greek kings|
|140–130 BCE||Heliocles I||to the|
|130 BCE-||Complete occupation of Bactria by the Yuezhi.||1st century CE)|