Darius I in the context of "Second Persian invasion of Greece"

Pontus (Ancient Greek: Πόντος Pontos) was a Hellenistic kingdom centered in the historical region of Pontus in modern-day Turkey, and ruled by the Mithridatic dynasty of Persian origin, which may have been directly related to Darius the Great of the Achaemenid dynasty. The kingdom was proclaimed by Mithridates I in 281 BC and lasted until its conquest by the Roman Republic in 63 BC. The Kingdom of Pontus reached its greatest extent under Mithridates VI the Great, who conquered Colchis, Cappadocia, Bithynia, the Greek colonies of the Tauric Chersonesos, and for a brief time the Roman province of Asia. After a long struggle with Rome in the Mithridatic Wars, Pontus was defeated.

The kingdom had three cultural strands, which often fused together: Greek (mostly on the coast), Persian, and Anatolian, with Greek becoming the official language in the 3rd century BC.

The ancient history of Afghanistan, also referred to as the pre-Islamic period of Afghanistan, dates back to the prehistoric era and the Helmand civilization around 3300–2350 B.C. Archaeological exploration began in Afghanistan in earnest after World War II and proceeded until the late 1970s during the Soviet–Afghan War. Archaeologists and historians suggest that humans were living in Afghanistan at least 50,000 years ago, and that farming communities of the region were among the earliest in the world. Urbanized culture has existed in the land from between 3000 and 2000 BC. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, and Iron ages have been found inside Afghanistan.

After the Indus Valley Civilisation stretched up to northeast Afghanistan, it was inhabited by the Iranic tribes and controlled by the Medes until about 500 BC when Darius the Great (Darius I) marched with his Persian army to make it part of the Achaemenid Empire. In 330 BC, Alexander the Great of Macedonia invaded the land after defeating Darius III of Persia in the Battle of Gaugamela. Much of Afghanistan became part of the Seleucid Empire followed by the Greco-Bactrian Kingdom. Seleucus I Nicator was defeated by Chandragupta Maurya and gave his daughter in a peace treaty. The land was inhabited by various tribes and ruled by many different kingdoms for the next two millennia. Before the arrival of Islam in the 7th century, there were a number of religions practiced in modern-day Afghanistan. Zoroastrianism and Ancient Iranian religions were practiced in western Afganistan (Khorasan and Herat). Hinduism and Buddhism was primarily practiced in regions of Eastern (Kabul) and South-Eastern Afganistan (Kandahar). The Kafiristan (present-day Nuristan) region, in the Hindu Kush mountain range, was not converted until the 19th century. They still follow the ancient Vedic religion (related to modern day Hinduism).

Old Persian cuneiform is a semi-alphabetic cuneiform script that was the primary script for Old Persian. Texts written in this cuneiform have been found in Iran (Persepolis, Susa, Hamadan, Kharg Island), Armenia, Romania (Gherla), Turkey (Van Fortress), and along the Suez Canal. They are mostly inscriptions from the time period of Darius I, such as the DNa inscription, as well as his son, Xerxes I. Later kings down to Artaxerxes III used more recent forms of the language classified as "pre-Middle Persian".

A satrap (/ˈsætrəp/) was a governor of the provinces of the ancient Median and Persian (Achaemenid) Empires and in several of their successors, such as in the Sasanian Empire and the Hellenistic empires. A satrapy is the territory governed by a satrap.

A satrap served as a viceroy to the king, though with considerable autonomy. The word came to suggest tyranny or ostentatious splendour, and its modern usage is a pejorative and refers to any subordinate or local ruler, usually with unfavourable connotations of corruption.

Megabyzus (Ancient Greek: Μεγάβυζος, a folk-etymological alteration of Old Persian Bagabuxša, meaning "God saved") was an Achaemenid Persian general, son of Zopyrus, satrap of Babylonia, and grandson of Megabyzus I, one of the seven conspirators who had put Darius I on the throne. His father was killed when the satrapy rebelled in 484 BCE, and Megabyzus led the forces that recaptured the city, after which the statue of the god Marduk was destroyed to prevent future revolts. Megabyzus subsequently took part in the Second Persian invasion of Greece (480–479 BCE). Herodotus claims that he refused to act on orders to pillage Delphi, but it is doubtful such orders were ever given.

Histiaeus (Ancient Greek: Ἱστιαῖος, died 493 BC), the son of Lysagoras, was a Greek ruler of Miletus in the late 6th century BC. Histiaeus was tyrant of Miletus under Darius I, king of Persia, who had subjugated Miletus and the other Ionian states in Asia Minor, and who generally appointed Greeks as tyrants to rule the Greek cities of Ionia in his territory.

Artaphernes (Greek: Ἀρταφέρνης, Old Persian: Artafarna, from Median Rtafarnah) was a brother of the Achaemenid king Darius I and held power circa 513–492 BC. He was appointed satrap of Lydia, which he governed from its capital of Sardis. As satrap of Lydia he had to deal with the Greeks, and played an important role in both the Siege of Naxos and in suppressing the Ionian Revolt.

Sattagydia or Thatagush (Old Persian: 𐎰𐎫𐎦𐎢𐏁 Thataguš, country of the "hundred cows") was one of the easternmost regions of the Achaemenid Empire, part of its Seventh tax district according to Herodotus, along with Gandārae, Dadicae and Aparytae. It was situated east of the Sulaiman Mountains up to the Indus in the Kurram River basin around Bannu in modern day's southern Khyber Pakhtunkhwa, Pakistan. Sattagydia was no longer mentioned by the third century BC, probably having been absorbed into one of the adjoining provinces.