How did Persia Conquer so Much so Quickly

Often referred to as the First Persian Empire, at its peak, this imperial power is believed to have reached from the Balkans in the west to the Indus Valley in the east. With roughly 5.5 million square kilometers under their authority, it's clear that the Achaemenids knew something those other trying empires did not, something that allowed them to become incredibly robust and widespread. So, how was the Achaemenid Empire so powerful? The Achaemenids began foremost as a dynasty in the early centuries BC. The first two patriarchs of this dynasty were Achaemenes and Teispedes, who together established the Kingdom of Anshan in the southwest of Iran encompassing the province of Pars. It was in this kingdom, around the start of the 6th century BC, that Cyrus the Great, the man who would go on to form the sturdy foundation of the Achaemenid Empire, was born. It is believed that Cyrus was the son of Cambyses I and the grandson of Cyrus I, all preceded by Teispedes. He was the heir to the throne of the Kingdom of Anshan, though his Achaemenid stronghold was not yet anything near to an empire. Instead, it was essentially a vassal state of the mightier Median Empire, and up until the point of Cyrus taking power, this would remain the case. In 559 BC, however, King Cambyses passed away and left the Anshan throne to his son and heir. Now, Cyrus was the ruler of a vassal state under the ultimate sovereignty of his maternal grandfather Astuages. What happened next is debated by multiple historians, as no one knows the exact reasoning behind what Cyrus chose to do, but we do know that for one reason or another, the new King of Anshan found himself at the helm of a rebellion against his grandfather in 553 BC. The revolt spread like wildfire and eventually reached the Median capital and Astuages himself. It's generally asserted that at this point, Cyrus managed to capture his grandfather but opted to spare his life and, for diplomatic reasons, marry his daughter. With all of this done, Cyrus was now the successor of the Median Empire, and thus, the first ruler of the Achaemenid Empire. In order to build a strong and lasting imperial power, one must first form a sturdy foundation, and that's precisely what Cyrus did. After he seized the helm of the empire, he saw easy submission from a handful of formerly Median vassals such as the Bactrians and Parthians. Over the following years, the new ruler would go on to subdue the vassals and establish a working governing system made up of a collection of semi-autonomous provinces or satrapies. And with this figured out, it was time to look externally. Cyrus, though seen by many as fair and just, was nevertheless a remarkable military commander who undeniably spent a considerable amount of time at war with his neighbors. One such neighbor was Lydia. While no one has managed to pin down the exact date of the war between the Lydians and the Achaemenids, the story of why the war began has become popular across the globe through writing and cinema. It's proclaimed that Crucis, king of the Lydians, was concerned about the growing pertinence of the young emperor from Persia and subsequently sought insight from the great oracle at Delphi. Crucis, possibly a result of an inflated ego or sense of security, assumes that this meant he would win the war and destroy the Achaemenid Empire. This, however, was the exact opposite of what would really occur. Instead of leveling the newfound empire to the east, the Lydians were in fact decimated. Cyrus had been warned of the building military presence at his border and began his own preparations for an immovable defense. Once Crucis officially launched the invasion, Cyrus hurried his army to meet them in the west. Through a combination of a powerful counter-offensive and poor tactical calculations by Crucis, the Achaemenids pushed back against their invaders and reached all the way to Sardis, capturing it and taking the whole of Asia Minor along with it. The Lydian kingdom had fallen, and this was just the beginning for Cyrus. Though it doesn't seem that Cyrus was particularly eager to launch conquests into the surrounding states in the name of territorial expansion, even aside from quelling local revolts within his own lands, the new emperor would regardless find himself at war with a neighbor yet again, this time with the Neo-Babylonian Empire. The conflict would last from 540 to 539 BC, and just as he'd done to the Lydians, Cyrus routed the Babylonians. The latter had grown increasingly dissatisfied with their contemporary ruler and his heir, inspiring Cyrus to take full advantage and style himself as the liberator of the people. Eventually, Babylon would fall to tactically savvy Achaemenids. Cyrus allowed the conquered king to live, sending him into exile to spare his life. The Persian ruler was then welcomed by the Babylonian people, demonstrating Cyrus' growing reputation as an ideal leader to many, largely due to the well-informed and intentioned policies he would swiftly enact. It was thus through his military prestige and wise oversight that he managed to build and maintain a remarkable foundation for the newly birthed Achaemenid Empire. However, Cyrus was only the first to rule this young imperial power, and after his death in 530 BC, expansion would continue. Cyrus was succeeded by his son, Cambyses II, who would go on to broaden the empire's borders even more aggressively than his father before him. First, Cyprus and Phoenicia would fall under Achaemenid sovereignty. Next, Cambyses set his sight on Egypt. In this endeavor, thanks to internal strife after the death of Pharaoh Amasis II in 526 BC, Cambyses would find great success. His invasion into Egypt saw the fall of the ruling dynasty and the capture of Egyptian territory by the Achaemenids. Furthermore, nearby states who feared an invasion into their own lands, such as Libya and Cyrene, shortly surrendered to the Persian Emperor before he could launch an offensive against them. Cambyses would then march farther into Africa towards Ethiopia, though in this particular campaign he failed, if Herodotus, who gives us much of the utilized accounts of the Achaemenids, is to be believed. Bardiya's reign would be short-lived, and he would be later deemed a fraud and a usurper, with the theory being that the real Bardiya had actually been killed by Cambyses in secret a while prior. A man and relative to Cyrus the Great by the name of Darius was particularly in favor of this theory, and consequently took it into his own hands to overthrow the suspected Bardiya and take the throne for himself. Darius too would become known as the Great due to his victorious efforts to expand the Achaemenid Empire to its peak during his three-decade-long reign. It was Darius the Great who would bring 40% of the world's population under the reign of the Achaemenids, which was an absolutely mind-blowing phenomenal feat, particularly for its time. And although the accomplishments of Darius were remarkable, those of his successors would sadly fall short, one after another. The Achaemenid Empire had reached its peak already, and no matter how miraculous, every peak is followed by a fall. Still, the empire would last until 330 BC, and the high point of its power would extend through the reign of Darius' immediate successor, Xerxes I, or later, Xerxes the Great. And even if the empire would inevitably fall at some point, there is no denying how powerful it became at its peak. Most attribute the how to none other than Cyrus himself. The reason is because Cyrus the Great not only created the Achaemenid Empire through his overthrow of the prior Median rule, but he also was a marvelous leader. Generally, his wars were fought only in response to internal or external aggression first, and in the case such as Babylon, when that was not entirely accurate, he still managed to portray himself to the Babylonian people as a liberator. And he, nevertheless, ruled as one once he took power, being also fair and for the people in the eyes of many throughout all of the territories he brought under his control. But Cyrus, of course, is not the only ruler of his people who can be credited for building the record-breaking empire. His son and successor too expanded the territorial holdings of the Persians. However, his reputation wasn't quite as great as his father's, or the later ruler, Darius the Great. And Darius, without question, should also take praise for pushing the empire to its peak through his endeavors and admirable leadership.