Euthydemus I in the context of "Antiochus III"

The Greco-Bactrian Kingdom (Greek: Βασιλεία τῆς Βακτριανῆς, romanized: Basileía tês Baktrianês, lit. 'Kingdom of Bactria') was a Greek kingdom during the Hellenistic period located in Central Asia and Afghanistan. The kingdom was founded by the Seleucid satrap Diodotus I Soter in about 256 BC, and continued to dominate Central Asia until its fall around 120 BC. At its peak the kingdom consisted of present-day Afghanistan, Tajikistan, Uzbekistan and Turkmenistan, and for a short time, small parts of Kazakhstan, Pakistan, India and Iran. An extension further east, with military campaigns and settlements, may have reached the borders of the Qin State in China by about 230 BC.

A Greek population was already present in Bactria by the 5th century BC. Alexander the Great had conquered the region by 327 BC, founding many cities, most of them named Alexandria, and further settling Macedonians and other Greeks. After the death of Alexander, control of Bactria passed on to his general Seleucus I Nicator. The fertility and the prosperity of the region led to the creation of the Greco-Bactrian kingdom under Diodotus by the early 3rd century BC, as a successor state of the Seleucid Empire. The Bactrian Greeks grew increasingly more powerful and invaded north-western India between 190 and 180 BC under king Demetrius, the son of Euthydemus. This invasion led to the creation of the Indo-Greek kingdom, which in turn was a successor to the Greco-Bactrian kingdom, and was subsequently ruled by the kings Pantaleon and Apollodotus I. Historical records indicate that many rich and prosperous cities were present in the kingdom, but only a few of them have been excavated, such as Ai-Khanoum and Bactra. The city of Ai-Khanoum, in north-eastern Afghanistan, had all the hallmarks of a true Hellenistic city with a Greek theater, gymnasium and some houses with colonnaded courtyards.

Demetrius I Anicetus (Ancient Greek: Δημήτριος Ἀνίκητος, romanized: Dēmḗtrios Aníkētos, "Demetrius the Unconquered"), also called Dimetriya in Indian sources, was a Greco-Bactrian king and the founder of the Indo-Greek kingdom, who ruled areas from Bactria to ancient northwestern India. He was the son of the Greco-Bactrian ruler Euthydemus I and succeeded him around 200 BC, after which he conquered extensive areas in what is now southern Afghanistan, Pakistan and northwestern India.

He was never defeated in battle and was posthumously referred to as "the Unconquered" (Ἀνίκητος, Aniketos) on the pedigree coins of his successor Agathocles of Bactria. Demetrius I may have been the initiator of the Yavana era, starting in 186–185 BC, which was used for several centuries thereafter.

Diodotus II Theos (Greek: Διόδοτος Θεός, Diódotos Theós, "Diodotus the God"; r. 235 – 225 BC) was the son and successor of Diodotus I Soter, who rebelled against the Seleucid empire, establishing the Graeco-Bactrian Kingdom. Diodotus II probably ruled alongside his father as co-regent, before succeeding him as sole king around 235 BC. He prevented Seleucid efforts to reincorporate Bactria back into the empire, by allying with the Parthians against them. He was murdered around 225 BC by Euthydemus I, who succeeded him as king.

Diodotus’ career was recounted by Apollodorus of Artemita in the Parthian History, but this text is lost, and surviving literary sources only mention him in passing. Thus, most details of Diodotus' life and career have to be reconstructed from numismatics.

Agathocles I Dicaeus (Ancient Greek: Ἀγαθοκλῆς Δικαῖος, romanized: Agathoklês Dikaîos, meaning "Agathocles the Just") was a Greco-Bactrian/Indo-Greek king, who reigned between around 190 and 180 BC. He was likely from the dynasty of Euthydemus I, but he is also known to have commemorated both Diodotus I and Antiochus Nicator.

The Euthydemid dynasty was a Hellenistic dynasty founded by Euthydemus I in 230 BC which ruled the Greco-Bactrian and Indo-Greek kingdoms throughout the Hellenistic period from 230 BC to 10 AD, upon the death of its last ruler, Strato III in Gandhara. For the genealogy of this dynasty, see Family tree of the Greco-Bactrian and Indo-Greek kings.

Zoilus I Dicaeus (Ancient Greek: Ζωΐλος Δίκαιος, romanized: Zōïlos Díkaios; 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.