Zoilus I Dikaios (Greek: Ζωΐλος Α΄ ὁ Δίκαιος; epithet means "the Just") was an Indo-Greek king who ruled in Afghanistan and Pakistan and occupied the areas of the Paropamisade and Arachosia previously held by Menander I. He may have belonged to the dynasty of Euthydemus I.
Zoilos used to be dated after the death of Menander, c. 130–120 BCE (Bopearachchi). Two coins of Zoilus I were however overstruck by Menander I  so Zoilos came to power while Menander was still alive and was perhaps his enemy. R. C. Senior has suggested some time between 150–135 BCE.
Zoilos I uses a silver coin type similar to that of Euthydemus II, son of Demetrius: Crowned Herakles standing, holding a wreath or diadem in his right hand, and a club and the lion skin in his left hand. On some of the coins, which are of lower artistic quality, Herakles is crowned by a small Nike. Zoilos I also struck rare gold-plated silver coins with portrait and Heracles.
The Indian-standard coins of Zoilos I also bear the Pali title "Dhramikasa" ("Follower of the Dharma"), probably related to Buddhism, appearing for the first time on Indo-Greek coinage. A few monolingual Attic tetradrachms of Zoilos I have been found. Zoilos inherited (or took) several monograms from Menander I.
His bronze coins are square and original in that they combine the club of Herakles with a Scythian-type bowcase (for a short recurve bow) inside a victory wreath, suggesting contacts or even an alliance with horse-mounted people originating from the steppes, possibly either the Scythians (future Indo-Scythians), or the Yuezhi who had invaded Greco-Bactria. This bow can be contrasted to the traditional Hellenistic long bow depicted on the coins of the eastern Indo-Greek queen Agathokleia.
Zoilos I and Herakles.
Coin of Zoilos I. Profile of the ruler, with Greek legend BASILEOS DIKAIOU ZOILOU "Of King Zoilos the Just". Metropolitan Museum of Art
|Greco-Bactrian and Indo-Greek kings, territories and chronology
Based on Bopearachchi (1991)
|Greco-Bactrian kings||Indo-Greek kings|
|West Bactria||East Bactria||Paropamisade
||Arachosia||Gandhara||Western Punjab||Eastern Punjab||Mathura|
|326-325 BCE||Campaigns of Alexander the Great in India||Nanda Empire|
|312 BCE||Creation of the Seleucid Empire||Creation of the Maurya Empire|
|305 BCE||Seleucid Empire after Mauryan war||Maurya Empire|
|280 BCE||Foundation of Ai-Khanoum|
|255–239 BCE||Independence of the
|Emperor Ashoka (268-232)|
|239–223 BCE||Diodotus II|
|230–200 BCE||Euthydemus I|
|200–190 BCE||Demetrius I||Sunga Empire|
|190-185 BCE||Euthydemus II|
|185–170 BCE||Antimachus I|
|180–160 BCE||Apollodotus I|
|175–170 BCE||Demetrius II|
|160–155 BCE||Antimachus II|
|170–145 BCE||Eucratides I|
|155–130 BCE||Yuezhi occupation,
loss of Ai-Khanoum
|130–120 BCE||Yuezhi occupation||Zoilos I||Agathokleia||Yavanarajya
|120–110 BCE||Lysias||Strato I|
|110–100 BCE||Antialcidas||Heliokles II|
|100 BCE||Polyxenos||Demetrius III|
|90–85 BCE||Nicias||Menander II||Artemidoros|
|Yuezhi occupation||Maues (Indo-Scythian)|
|75–70 BCE||Vonones||Telephos||Apollodotus II|
|55–35 BCE||Azes I (Indo-Scythians)||Zoilos II|
|55–35 BCE||Vijayamitra/ Azilises||Apollophanes|
|25 BCE – 10 CE||Gondophares||Zeionises||Kharahostes||Strato II
|Gondophares (Indo-Parthian)||Rajuvula (Indo-Scythian)|
|Kujula Kadphises (Kushan Empire)||Bhadayasa