Cambyses II (Old Persian: 𐎣𐎲𐎢𐎪𐎡𐎹 Kɑmboujie, (522 BCE) son of Cyrus the Great (r. 559–530 BCE), was a king of kings of the Achaemenid Empire. Cambyses's grandfather was Cambyses I, king of Anshan. Following Cyrus the Great's conquest of the Near East and Central Asia, Cambyses II further expanded the empire into Egypt during the Late Period by defeating the Egyptian pharaoh Psamtik III during the battle of Pelusium in 525 BCE. After the Egyptian campaign and the truce with Libya, Cambyses invaded the Kingdom of Kush (located in what is now the Republic of Sudan) but with little success.

When Cyrus the Great conquered Babylon in 539 BCE, Cambyses was employed in leading religious ceremonies. In the cylinder which contains Cyrus's proclamation to the Babylonians, Cambyses's name is joined to his father's in the prayers to Marduk. On a tablet dated from the first year of Cyrus, Cambyses is called king of Babylon, although his authority seems to have been ephemeral. Only in 530 BCE, when Cyrus set out on his last expedition into the East, did Cyrus associate Cambyses with the throne. Numerous Babylonian tablets of the time date from the accession and the first year of Cambyses, when Cyrus was "king of the countries" (i.e., of the world).

Artaxerxes I (Greek: Ἀρταξέρξης, Old Persian𐎠𐎼𐎫𐎧𐏁𐏂𐎠 Artaxšaça, "whose rule (xšaça < *xšaϑram) is through arta (truth)";Modern Persian اردشیر یکم Ardašir; the name has nothing to do with Xerxes) was the sixth king of kings of the Achaemenid Empire from 465 BCE to 424 BCE. He was the son of Xerxes I of Persia and Amestris, daughter of Otanes.

He may have been the "Artasyrus" mentioned by Herodotus as being a Satrap of the royal satrapy of Bactria.

In Greek sources he is also surnamed μακρόχειρ Macrocheir (Latin: 'Longimanus'), allegedly because his right hand was longer than his left.

After Persia had been defeated at Eurymedon, military action between Greece and Persia was at a standstill. When Artaxerxes I took power, he introduced a new Persian strategy of weakening the Athenians by funding their enemies in Greece. This indirectly caused the Athenians to move the treasury of the Delian League from the island of Delos to the Athenian acropolis. This funding practice inevitably prompted renewed fighting in 450 BCE, where the Greeks attacked at the Battle of Cyprus. After Cimon's failure to attain much in this expedition, the Peace of Callias was agreed between Athens, Argos and Persia in 449 BCE.

Cyrus II of Persia (Old Persian: Kuruš (c. 600 BC or 576 BC–530 BC), commonly known as Cyrus the Great, also known as Cyrus the Elder, was the founder of the Achaemenid Empire. Under his rule, the empire embraced all the previous civilized states of the ancient Near East, expanded vastly and eventually conquered most of Southwest Asia and much of Central Asia, parts of Europe and the Caucasus. From the Mediterranean sea and Hellespont in the west to the Indus River in the east, Cyrus the Great created the largest empire the world had yet seen. He also pronounced one of the first historically important declarations of human rights via the Cyrus Cylinder sometime between 539-530 BCE.

The reign of Cyrus the Great lasted between 29 and 31 years. Cyrus built his empire by conquering first the Median Empire, then the Lydian Empire and eventually the Neo-Babylonian Empire. Either before or after Babylon, he led an expedition into central Asia, which resulted in major campaigns that were described as having brought "into subjection every nation without exception". Cyrus did not venture into Egypt, as he himself died in battle, fighting the Massagetae along the Syr Darya in December 530 BC. He was succeeded by his son, Cambyses II, who managed to add to the empire by conquering Egypt, Nubia, and Cyrenaica during his short rule.