Bartia was the king of persia brother of cambises and son of Cyrus. In 522 bce he was the most powerful man on the planet but within a few months he was gone in his place stood a man named Darius. Here there are two historical narratives there's one narrative officially endorsed and promoted by darius himself after he secured his place on the persian throne . 

This narrative says that the bardia on the throne of persia was actually an impostor some random guy pretending to be the real bardia the real bardia says the narrative was actually executed by cambises at some time during his reign the narrative makes the additional claim that both Darius and Cyrus descend from a common ancestor named akimenes making them part of the same achaemenid dynasty. 

 Herodotus endorses this narrative relaying the story of a contest between the best of persia's nobles that eventually leads to Darius winning the throne by merit the other narrative which is the one endorsed by modern historical consensus says that bardia was the real bartia and that he was a legitimate successor to cambyses darius was a usurper this narrative also states that darius was an outsider to the dynasty of cyrus and that the supposed common ancestor never existed given that cambyses reign was much better than the conventional narrative purports Darius's dubious claim that Bardia was summarily killed and then impersonated by an imposter looks a little ridiculous the inevitable conclusion is that darius was illegitimate a violent act. 

Even at the time many persian subjects didn't buy Darius's story within the first year of his seizure of the throne areas across the persian empire including egypt and babylon had risen in revolt against his rule luckily for darius he still had the army on his side which allowed him to put down many of the revolts against his authority within a couple years of rising to the throne he traveled from susa to babylon to egypt everywhere he went. 

He reestablished persian authority by 518 bce the persian empire was again unified under the undisputed rulership of one king during these early years darius also worked on crafting his public image he created inscriptions which promoted his narrative about the rise to power and connected him to the royal dynasty of cyrus this was important for ensuring that his rule as well as the rule of his successors would remain stable and legitimate. 

He also married atossa the daughter of Cyrus the great and originally the wife of cambises after he unified the domains of persia darius worked on expanding the empire yet again there were still frontiers for persia to breach and darius led the persian armies in the process. He went east first fighting wars against the nomadic peoples of the steppe those who had killed cyrus years before he also pushed into the indus river valley conquering the whole region by 513 bce the region was a lucrative conquest among the richest in the world although darius was a great conqueror in his own right.

 He is more remembered as an administrator he was the architect of the persian empire effectively creating the systems of government and finance that would sustain the empire for two more centuries after his death he formally oversaw the appointment of the sad traps to oversee the administrative divisions which improved central control over persia's satrapies at the same time darius continued to respect local forms of government and authority guarding against future revolts. 

He also established a tribute system which effectively stood in place of direct taxation and was made proportional to the wealth of the tributary regions the tribute system effectively curtailed the perception that the persian government was oppressive by limiting direct interference by persian authorities in the daily life and routine affairs of taxation darius also commissioned many building projects throughout the empire he created a new capital for the empire at persepolis building a grand palace complex along with all the necessities for a great city in egypt he restored several temples and constructed new ones perhaps his most important construction project was the completion of the canal of the pharaohs which connected the nile river to the red sea.

 Along with his conquest of the indus river valley this canal secured an unbroken line of maritime trade between india and the mediterranean if trajan was Cyrus Hadrian was Darius Darius's conquests were not finished in the early 500s he led a massive army across the hellespont the first time a near eastern empire had made significant moves into europe reportedly he used a massive pontoon bridge the famous bridge of boats once in europe .

He subdued the thracian tribes after fierce fighting and pushed into macedonia stopping just before reaching the main greek cities he also crossed the danube in an attempt to subjugate the tribal peoples there but he was unsuccessful and retreated to thrace by this point darius had already brought the persian empire to its greatest extent but he wanted more .

 Specifically he wanted the greeks Darius's quarrel with the greeks specifically the greeks of athens and a few other cities was the issue of the ionian revolt in the 490s athens had sent assistance to the organization of a revolt of greek cities in asia minor which were under persian authority this revolt was swiftly crushed by the combined persian naval and land forces the only thing athens had succeeded at was in effect pissing off the king of kings darius decided that the athenians and their associates had to be punished and in 490 Bce. He sent a maritime expedition to land in greece and march on athens this expedition had with it a man named hippias who had been tyrant of athens before the establishment of democracy in 508 bce the persian commander hoped to install hippies as the new ruler of the city with the promise that athens would then become a loyal subject of persia this along with persian possessions in macedon would provide a staging point for a potential war against the rest of greece followed by an incorporation of the greek mainland into the persian empire the persian expedition landed at the bay of marathon at a point about 25 miles from the city of Athens.  

They were met immediately by a smaller force of athenian hoplites the athenians knew the terrain better and took proper defensive positions to contain the persians numbers are unclear but it's likely that the athenians were outnumbered at least two to one possessing about ten thousand soldiers while the persians had over twenty thousand the athenians were waiting for the arrival of the spartan army which had promised to give them aid but was delayed by a religious festival and would not arrive for a couple weeks their ticket to survival against this larger persian force seemed to be delay however something changed before the spartans arrived the athenians attacked the persian positions at marathon first contact between the heavily armed hoplites and lightly armed persian infantry proved that the weight of the athenian line could overwhelm. 

The persians the persian center buckled but was reinforced by superior persian numbers the battle was eventually won when athenian troops on the flanks managed to envelop the persian army causing a route the persians ran back to their ships managing to retreat in mostly good order athens had survived greece had survived it was an incredible victory an underdog city-state defeating the greatest empire in the world in the aftermath the athenians sent a runner to cover the distance between marathon and athens and relay news of the victory guess they couldn't spare a horse he got there reported the victory and then died. Upon hearing of the defeat Darius was frustrated he began preparing for another invasion of greece far larger than marathon this was to crush the greeks once and for all the people who had inexplicably managed to defeat persia they would not do so a second time before he could lead the expedition himself though his health began to fail darius died in 486 Bce having ruled persia for almost four decades on his tomb were written the words I am darius the great king king of kings king of countries containing all kinds of men king in this great earth far and wide you .