Herodotus ( /hɨˈrɒdətəs/; Ancient Greek: Ἡρόδοτος Hēródotos) was an ancient Greek historian who was born in Halicarnassus, Caria (modern day Bodrum, Turkey) and lived in the fifth century BC (circa 484 – 425 BC). He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a well-constructed and vivid narrative.The Histories—his masterpiece and the only work he is known to have produced—is a record of his "inquiry" (or ἱστορία historía, a word that passed into Latin and acquired its modern meaning of "history"), being an investigation of the origins of the Greco-Persian Wars and including a wealth of geographical and ethnographical information. Although some of his stories were fanciful, he claimed he was reporting only what had been told to him. Little is known of his personal history.

The Histories, otherwise known as The Researches or The Inquiries, were divided by later Alexandrian editors into nine books, named after the nine Muses: the "Muse of History", Clio, representing the first book, then Euterpe, Thaleia, Melpomene, Terpsichore, Erato, Polymnia, Ourania and Calliope for books 2 to 9, respectively. At its simplest and broadest level of meaning, The Histories is structured as a dynastic history of four Persian kings:

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.