Darius Hystaspes or Darius I or Darius the Great (डैरियस, डारियस) (550–486 BCE), formally known as Darius the Great, was the third king of the Achaemenid Empire. He held the empire at its peak, when it included much of West Asia, the Caucasus, Central Asia, parts of the Balkans (Bulgaria-Romania-Panonia), portions of north and northeast Africa including Egypt (Mudrâya), eastern Libya, coastal Sudan, Eritrea, as well as most of Pakistan, the Aegean Islands and northern Greece/Thrace-Macedonia.
Darius ascended the throne
Darius ascended the throne by overthrowing the alleged magus usurper of Bardiya with the assistance of six other Persian noble families; Darius was crowned the following morning. The new king met with rebellions throughout his kingdom and quelled them each time. A major event in Darius's life was his expedition to punish Athens and Eretria for their aid in the Ionian Revolt and subjugate Greece. Darius expanded his empire by conquering Thrace and Macedon and invading Scythia, home of the Scythians, nomadic tribes who invaded Media and had previously killed Cyrus the Great.
H. W. Bellew  writes that At that period, about 450 B.C., Ariana, the Khorasan, or Afghanistan, we speak of, formed the eastern portion of the Empire of Darius Hystaspes — Dara son of Gushtasp. This Darius belonged to a Persian family or tribe, whose seat was in the north-eastern part of the country we are discussing — in the Bakhtar province, the capital of which was the city of Balkh, called by the Arabs Um-al-bilad or "Mother of Cities," on account of its great antiquity. He succeeded, about 521 B.C., to the empire founded by Cyrus (Kurush), and enlarged and consolidated by his son and successor Cambyses (Kamhojia, Kamhohji), Cyrus — whose mother was called Mandane (Mandana ; perhaps a princess of the Mandan tribe), and said to be a Mede, and whose father was called Cambyses (Kamhohji ; probably a chieftain of the Kamboh tribe) — having reduced the Medes and conquered the kingdom of Crcesus the Lydian (Ludi) thereby became master of all the territory extending from the Indus to the Hellespont.
Darius organized the empire
Darius organized the empire by dividing it into provinces and placing satraps to govern it. He organized a new uniform monetary system, along with making Aramaic the official language of the empire. Darius also worked on construction projects throughout the empire, focusing on Susa, Pasargadae, Persepolis, Babylon and Egypt. Darius devised a codification of laws for Egypt. He also had the cliff-face Behistun Inscription carved, an autobiography of great modern linguistic significance. Darius also started many massive architectural projects, including magnificent palaces in Persepolis and Susa.
Behistun Inscription and Herodotus
Darius left a tri-lingual monumental relief on Mount Behistun which was written in Elamite, Old Persian and Babylonian between his coronation and his death. The inscription begins with a brief autobiography with his ancestry and lineage. To aid the presentation of his ancestry, Darius wrote down the sequence of events which occurred after the death of Cyrus the Great. Darius mentions several times that he is the rightful king by the grace of Ahura Mazda, the Zoroastrian God. In addition, further texts and monuments from Persepolis have been found, including a fragmentary Old Iranian inscription from Gherla, Romania (Harmatta) and a letter from Darius to Gadates, preserved in a Greek text of the Roman period.
Herodotus, a Greek historian and author of The Histories, provided an account of many Persian kings and the Greco-Persian Wars. He wrote an extensive amount of information on Darius which spans half of book 3, along with books 4, 5 and 6. It begins with the removal of the alleged usurper Gaumata and continues to the end of Darius's reign.
Darius was born as the eldest of five sons to Hystaspes and Rhodugune in 550 BCE. Hystaspes was a leading figure of authority in Persia, which was the homeland of the Persians. Darius's inscription states that his father was satrap of Bactria in 522 BCE. According to Herodotus, Hystaspes was the satrap of Persis, although most historians state that this is an error. Also according to Herodotus (III.139), Darius, prior to seizing power and "of no consequence at the time", had served as a spearman (doryphoros) in the Egyptian campaign (528–525 BCE) of Cambyses II, then the Persian Great King. Hystaspes was an officer in Cyrus's army and a noble of his court.
Before Cyrus and his army crossed the Aras River to battle with northern tribes, he installed his son Cambyses II as king in case he should not return from battle. However, once Cyrus had crossed the Aras River he had a dream with a vision of Darius in which he had wings atop his shoulders and stood upon the confines of Europe and Asia (the whole known world). When Cyrus awoke from the dream, he inferred it as a great danger to the future security of the empire, as it meant that Darius would one day rule the whole world. However, his son Cambyses was the heir to the throne, not Darius, causing Cyrus to wonder if Darius was forming treasonable and ambitious designs. This led Cyrus to order Hystaspes to go back to Persis and watch over his son strictly, until Cyrus himself returned. Darius did not seem to have any treasonous thoughts as Cambyses II ascended the throne peacefully, and through promotion Darius was eventually elevated to Cambyses's personal lancer.
Darius was son of Hystaspes and grandson of Arsames, both men belonging to the Achaemenid tribe, and being alive when Darius ascended the throne. Darius justifies his ascension to the throne with his lineage tracing back to Achaemenes, even though he was distantly related. For these reasons,
- Darius married Atossa, daughter of Cyrus, with whom he had four sons, 1. Xerxes, 2. Achaimenes, 3. Masistes and 4. Hystaspes.
- He also married Artystone, another daughter of Cyrus, with whom he had two sons, Arsames and Gobryas.
- Darius also married Parmys, the daughter of Bardiya, with whom he had a son, Ariomardos.
- Furthermore, Darius married Phratagone, with whom he had two sons, Abrokomas and Hyperantes.
- He also married another woman of the nobility, Phaidime, the daughter of Otanes. It is unknown if he had children with her.
- Before these royal marriages, Darius married a commoner with whom he had three sons, Artobarzanes(the first born), Arabignes and Arsamenes, while daughters are not known.
Although Artobarzanes was the first born of Darius, Xerxes became heir and next king through the influence of Atossa, who had great authority in the kingdom, as Darius loved her, of all of his wives, most.
Jat history connections
We find Karwara clan in the history of Iran as Karpaya. Herodotus has written that at the time of war of Darius the Great and his son, Xerxes with Greeks they had an army of Indian Jats. In Sojahaj district of Iran there is a tribe called Karpaya which is of Karav people. It is possible that these people moved from Mathura district. There capital might be at Karav, a place in Mathura district. At present this area of Mathura is occupied by Hanga Jats. 
H. W. Bellew writes that Seventh satrapy of Darius consisted of Sattagydai, or "Sattag kindred," are now represented by the Khattak, Shattak, Sattak, and Shitak or Sitak tribes of the Indus border .
Bhim Singh Dahiya  writes that Confounding the brave Mandas with the effete Medes was the most unfortunate event in history. The mistake become so prevalent that even a proverb was invented in English equal to the effect that a certain thing is as unchangeable-as the laws of Medes and Persians. The mistake was detected when the monuments of Nabonodus and Cyrus were unearthed. It was then discovered that the whole history was based upon a philological mistake. It was found that the name of the empire and its people, was not Medes but Manda. In the words of Prof. Sayce, in his well known book, Ancient Empires of The East; "when in two generations which succeeded Darius Hustaspes, Cyrus, became the founder of the present empire, the Medes and the Manda were confounded, one with the other. Astyages, the suzerain of Cyrus, was transformed into a Mede and the city of Ecbatana, into the capital of a Median empire. The illusion has lasted down to our own age. There was no reason for doubting the traditional story, neither in the pages of the writers of Greece and Rome, nor in those of the old testament, nor even in the great inscriptions of Darius in Behistun, did there seem to, be anything to cause suspicion upon it.
Bhim Singh Dahiya writes that the most solid example of the existence of the Jats is found in the records of the Van kingdom of Armenia. Every single name of that kingdom, whether it is of cities or of the various clans, can-only be identified with the name Jat or its various clans. After this ninth century B.C. king of the Yen/Ben (present Beniwal clan) we come across the next kingdom of the Maan clan called the Mannai kingdom on the Lake Urumiya. This Lake Urumiya was the Centre of the Jats in the ninth century B.C. and earlier; and it was from here that Moika, the Urumiy scion of Kushana inscriptions came to India in the first century A.D. This Lake Urumiya is situated in the western part of Iran, or bordering Turkey. It was the reputed birth place of Zoroaster.  This 'Maan kingdom' on the Lake Urumiya, as well as the earlier Venwal kingdom on the Lake Ven, were later merged in the seventh century B.C. in the kingdom of Manda clan, under Huvakshatra (Cyaxeres of the Greeks). This empire of the Mandas was superseded by Cyrus the Great and at that time , many Jats, who refused to accept the change of government, went into various directions. Many of them came to India and some of them spread into Europe where they were called Gots or Goths. Those who remained there and accepted the change of dynasty by expressing their loyalty to Darius, were called Euer Gatae, meaning the "benefactor" Jats, obviously benefactors to the Persians and not to the Jats' cause.
Bhim Singh Dahiya In the subsequent paragraph we shall give evidence to show that these people came to India when the Jat empire of the Mandas was superseded under Cyrus the Great and Darius. It is also a well known fact that when with the help of General Harpagus, the last Manda emperor Ishtuvegu was taken prisoner by Cyrus the Great, many Central Asian Jats had to run to India and in other directions. Those who did not lend their loyalty to Cyrus had to flee. Many others had to flee under his successor, Darius. Jean Przyluski calls them Bahlikas from Iran and Central Asia.
Bhim Singh Dahiya Further we have the Uttara Madra (northern Madra) and the southern Madra, the latter being in the Punjab. Cambridge Ancient History mentions, "the land of Uttara Pashtum", i.e., northern Pashtoons, somewhere near Armenia. Herodotus, too, mentions the Pashtoons at two different places; one as part of the thirteenth satrapy of Darius (with Armenia)22 and other on the upper Indus, i.e., modern Afghanistan.23 Herodotus, significantly mentions that the Ponians, a colony of the Tukarians, were shifted by Darius from Black sea area to Asia, perhaps near about Bactria.
From the 7th century BC onwards, the Getae came into economic and cultural contact with the Greeks, who were establishing Colonies in antiquity|colonies on the western side of Pontus Euxinus, nowadays the Black Sea. The Getae are mentioned for the first time together in Herodotus (4.93-97) in his narrative of the Scythian campaign of Darius I in 513 BC. According to Herodotus, the Getae differed from other Thracian tribes in their religion, centered around the god (daimon) Zamolxis whom some of the Getae called Gebeleizis.
During the period that the Odrysian kingdom flourished between the 5th century BC and the 3rd century BC, the Getae were mostly under Odryssian rule, serving them militarily, especially as cavalry, for which they were famous. After the disintegration of the Odrysian kingdom, smaller Getic principalities began to consolidate themselves.
Before setting out on his Persian expedition, Alexander the Great defeated the Getae and razed one of their settlements. In 313, the Getae formed an alliance with Callatis, Odessos, and other western Pontic Greek colonies against Lysimachus, who held a fortress at Tirizis (modern Kaliakra).
Ram Swarup Joon  writes with reference to Todd's Rajasthan (based upon the writings of Justin and Herodotus), thousands of years before Christ, the Dahiya Mahajati tribe lived on the eastern bank of the River Sihun (Oxus). The Heir, Bhullar and Sihag sub-tribes lived in the adjoining country. The Dahiya Jats took part in the battle between Darius and Alexander.
An Inquiry Into the Ethnography of Afghanistan By H. W. Bellew (p.9) tells ....But from our more extended inquiry the Baraki of Afghanistan appear to be no other than the modern representatives of the captive Greeks who were transported, in the sixth century before Christ, by Darius Hystaspes, king of Persia, from the Libyan Barke to the Baktrian territory, as recorded by Herodotus.
The district in Baktria to which the Barkai of Herodotus were transported would appear to be the present Baghlan ; and the existing village of Baraki Barak there probably marks the site of the village they there built and named Barke. (HW Bellew, p.10)
डेरियस का सीथिया तथा थ्रेश राज्य के शासक जाटों से युद्ध
वह अपनी सेना को थ्रेश (बुल्गारिया) देश की ओर ले गया। फिर उसने डेन्यूब नदी को पार करके सीथियन जाटों पर आक्रमण कर दिया जो कि इससे भी अधिक वीर एवं युद्धविद्या में निपुण थे। सीथियन जाटसेना डेरियस को फुसलाने हेतु पीछे को हट गई। डेरियस ने सीथिया के राजा को यह सन्देश भेजा -
- “सीथिया देश के राजा, आप मेरे से दूर क्यों भाग रहे हो? यदि आप मेरे तुल्य हो तो ठहरो और युद्ध करो। यदि नहीं हो तो भागने की आवश्यकता नहीं, आप मुझे अपनी भूमि एवं जल सौंप दो और आत्मसमर्पण कर दो, जिसकी शर्तें सन्धि द्वारा तय की जा सकती हैं।”
इस सन्देश का उत्तर सीथियन राजा ने डेरियस को भेजा, जो कि आदर्शभूत जाट उत्तर है। सन्देश में कहा गया कि
- “फारस के सम्राट्, मैं सूर्य भगवान् के अलावा अन्य किसी से नहीं डरता। मैं भागता नहीं हूं तथा भूमि और पानी आपको नहीं दूंगा। यद्यपि मैं आपको बड़े योग्य उपहार भेजता हूं।”
उसने अपने दूत द्वारा एक पक्षी, एक चूहा, एक मेंढक और पांच तीर उपहार के तौर पर भेज दिये। डेरियस ने अनुमान लगाया कि चूहा भूमि को सूचित करता है तथा मेंढक पानी को। तदनुसार सीथियन ने हम को भूमि एवं पानी देना स्वीकार कर लिया है और आत्मसमर्पण कर रहे हैं। परन्तु डेरियस का ससुर जो कि एक चतुर सेनापति था, ने उसको इस उपहार का सत्य अर्थ इस तरह से बताया - “सिवाय इसके कि तुम पक्षी बनकर आकाश में उड़ जाओ या चूहे बनकर भूमि के भीतर चले जाओ या मेंढक बनकर पानी में चले जाओ, तुम में से एक भी जीवित वापिस नहीं जा सकता, हमारे तीर तुम्हारे हृदयों को छेद देंगे।” डेरियस यह समझकर कि मेरी सेना सीथियन सेना के फन्दे में फंसने वाली है, जान बचाकर डेन्यूब नदी को पार कर गया। अन्त में
जाट वीरों का इतिहास: दलीप सिंह अहलावत, पृष्ठान्त-355
वह सूसा को चला गया और एक सेना अपने वीर जनरल मेगाबाज़स (Megabazus) के नेतृत्व में देश में छोड़ गया। थ्रेस के जाटों ने इस जनरल को अपने अधीन कर लिया। इस तरह से थ्रेस के जाट तथा डैन्यूब नदी के प्रदेशों के शासक सीथियन जाट और अमू दरिया के उत्तर में शासक कांग जाट स्वतन्त्र रहे।