Achaemenid dynasty in the context of "Kingdom of Pontus"

The Achaemenid Empire (/əˈkiːmənɪd/ ə-KEE-mə-nid; Old Persian: 𐎧𐏁𐏂, Xšāça, lit. 'The Empire' or 'The Kingdom') was an ancient Iranian empire founded by Cyrus the Great of the Achaemenid dynasty in 550 BC. At peak, its territorial extent was roughly 5.5 million square kilometres (2.1 million square miles), making it the largest empire of its time. Based in the Iranian plateau, it stretched from the Balkans and Egypt in the west to the Indus Valley in the east, including Anatolia, Cyprus, Mesopotamia, the Levant, parts of Eastern Arabia, and large parts of Central Asia.

By the 7th century BC, the region of Persis, located in the southwestern part of the Iranian plateau, had been settled by Persians. From Persis, Cyrus rose and defeated Media, Lydia, and the Neo-Babylonian Empire, thus marking the establishment of a new imperial polity in the ancient Near East. While its conquests were largely successful in most regions, the Achaemenid Empire's attempts to expand into Greece proved extremely difficult over the course of decades of wars and multiple kings, ultimately resulting in its defeat in the Greek mainland.

Herodotus (Ancient Greek: Ἡρόδοτος, romanized: Hēródotos; c. 484 – c. 425 BC) was a Greek historian and geographer from the Greek city of Halicarnassus (now Bodrum, Turkey), under Persian control in the 5th century BC, and a later citizen of Thurii in modern Calabria, Italy. He wrote the Histories, a detailed account of the Greco-Persian Wars, among other subjects such as the rise of the Achaemenid dynasty of Cyrus. He has been described as "The Father of History", a title conferred on him by the ancient Roman orator Cicero.

The Histories primarily cover the lives of prominent kings and famous battles such as Marathon, Thermopylae, Artemisium, Salamis, Plataea, and Mycale. His work deviates from the main topics to provide a cultural, ethnographical, geographical, and historiographical background that forms an essential part of the narrative and provides readers with a wellspring of additional information.

Greater Iran or Greater Persia (Persian: ایران بزرگ Irān-e Bozorg), also called the Iranosphere or the Persosphere or Iranzamin (Persian: ایران‌زمین Irān-zamin), is a term used to refer to a broader cultural sphere that has been influenced, at least to some degree, by Iranian peoples and Iranian languages, and primarily includes the Iranian plateau, the South Caucasus, Central Asia, the Indian subcontinent, and historically stretched as far east as the Tarim Basin.

The regions which make up Greater Iran are defined by having long been under the rule of various Iranian empires and dynasties, during which the local populace gradually absorbed Iranian influence and assimilated it into their cultural and linguistic traditions; or those where a considerable Iranian population settled and retained their culture, such as in the areas surrounding the Iranian plateau. It is referred to as the "Iranian Cultural Continent" by Encyclopædia Iranica.

Cyrus II of Persia (c. 600 – 530 BC), commonly known as Cyrus the Great, was the founder of the Achaemenid Empire. Hailing from Persis, he brought the Achaemenid dynasty to power by defeating the Median Empire and embracing all of the previous civilized states of the ancient Near East, expanding vastly across most of West Asia and much of Central Asia to create what would soon become the largest empire in history at the time. The Achaemenid Empire's greatest territorial extent was achieved under Darius the Great, whose rule stretched from Southeast Europe in the west to the Indus Valley in the east.

After absorbing the Median Empire, Cyrus conquered Lydia and eventually the Neo-Babylonian Empire, granting him control of Anatolia and the Fertile Crescent, respectively. He also led a major expedition into Central Asia, where his army brought "into subjection every nation without exception" before he allegedly died in battle with the Massagetae, a nomadic Eastern Iranian people, along the Syr Darya in December 530 BC. However, according to Xenophon of Athens, Cyrus did not die fighting and had instead returned to the capital city of Pasargadae. Regardless of the date of his death, he was succeeded by his son Cambyses II, whose campaigns into North Africa led to the conquests of Egypt, Nubia, and Cyrenaica during his short rule.

Old Persian is one of two directly attested Old Iranian languages (the other being Avestan) and is the ancestor of Middle Persian (the language of the Sasanian Empire). Like other Old Iranian languages, it was known to its native speakers as ariya (Iranian). Old Persian is close to both Avestan and Vedic Sanskrit, and all three languages are highly inflected.

Old Persian appears primarily in the inscriptions, clay tablets and seals of the Achaemenid era (c. 600 BCE to 300 BCE). Examples of Old Persian have been found in what is now Iran, Romania (Gherla), Armenia, Bahrain, Iraq, Turkey and Egypt, with the most important attestation by far being the contents of the Behistun Inscription (dated to 522 BCE).

The monarchs of Iran ruled for over two and a half millennia, beginning as early as the 8th century BC and enduring until the 20th century AD. The earliest Iranian monarch is generally considered to have been either Deioces of the Median dynasty (c. 727–550 BC) or Cyrus the Great of the Achaemenid dynasty (550–330 BC). The last Iranian monarch was Mohammad Reza Pahlavi of the Pahlavi dynasty (1925–1979), who was overthrown in the Iranian Revolution. Since then, Iran has been governed by theocratic supreme leaders.

In classical antiquity, Iran reached the peak of its power and prestige under the Achaemenid Empire, which stretched from Egypt and parts of Southeast Europe in the west to the Indus Valley and parts of Central Asia in the east. By 323 BC, the Achaemenid Empire's territories had been conquered by the Macedonian Empire during the Wars of Alexander the Great, bringing Iran into the Hellenistic sphere. In the Wars of the Diadochi, the Seleucid Empire (305–129 BC) assumed control of Iran. Native Iranian rule was revived with the establishment and expansion of the Parthian Empire (247 BC–224 AD) and then the Sasanian Empire (224–651), which existed until the Arab conquest of Iran.

The Neo-Assyrian Empire was the fourth and penultimate stage of ancient Assyrian history. Beginning with the accession of Adad-nirari II in 911 BC, the Neo-Assyrian Empire grew to dominate the ancient Near East and parts of South Caucasus, North Africa and Eastern Mediterranean throughout much of the 9th to 7th centuries BC, becoming the largest empire in history up to that point. Because of its geopolitical dominance and ideology based in world domination, the Neo-Assyrian Empire has been described as the first world empire in history. It influenced other empires of the ancient world culturally, administratively, and militarily, including the Neo-Babylonians, the Achaemenids, and the Seleucids. At its height, the empire was the strongest military power in the world and ruled over all of Mesopotamia, the Levant and Egypt, as well as parts of Anatolia, Arabia and modern-day Iran and Armenia.

The early Neo-Assyrian kings were chiefly concerned with restoring Assyrian control over much of northern Mesopotamia, eastern Anatolia and Levant, since significant portions of the preceding Middle Assyrian Empire (1365–1050 BC) had been lost during the late 11th century BC. Under Ashurnasirpal II (r. 883–859 BC), Assyria once more became the dominant power of the Near East, ruling the north undisputed. Ashurnasirpal's campaigns reached as far as the Mediterranean, and he oversaw the transfer of the imperial capital from the traditional city of Assur to the more centrally located Kalhu (later known as Calah in the Bible and Nimrud to the Medieval Arabs) The empire grew even more under Ashurnasirpal's successor Shalmaneser III (r. 859–824 BC), though it entered a period of stagnation after his death, referred to as the "age of the magnates". During this time, the chief wielders of political power were prominent generals and officials, and central control was unusually weak. This age came to an end with the rule of Tiglath-Pileser III (r. 745–727 BC), who re-asserted Assyrian royal power and more than doubled the size of the empire through wide-ranging conquests. His most notable conquests were Babylonia in the south and large parts of the Levant. Under the Sargonid dynasty, which ruled from 722 BC to the fall of the empire, Assyria reached its apex. Under Sennacherib (r. 705–681 BC), the capital was transferred to Nineveh, and under Esarhaddon (r. 681–669 BC) the empire reached its largest extent through the conquest of Egypt. Despite being at the peak of its power, the empire experienced a swift and violent fall in the late 7th century BC, destroyed by a Babylonian uprising and an invasion by the Medes. The causes behind how Assyria could be destroyed so quickly continue to be debated among scholars.