Son of Hystaspes, member of Achaemenid (royal) clan

Heir after deaths of Cambyses and Smerdis, sons of Cyrus the Great
Conspired with Otanes to murder the false Smerdis
Won the kingship through his horse
The first rider whose horse neighed would be king
His groom fixed matters so that Darius’ horse neighed first
Conquered north eastern India
Fought a war unsuccessfully against the nomadic Scythians of central Asia

The Ionian Revolt 500--493 B.C.
During his reign the Ionian Greek cities and islands revolted against Persia
The Milesians and the Athenians burned Sardis
Darius’ reaction: “Laying aside all thought concerning the Ionians, who would, he was sure, pay dear for their rebellion, he asked who the Athenians were and, being informed, called for his bow, and placing an arrow on the string, shot upward into the sky, saying, as he let fly the shaft, ‘Grant me, Zeus, to revenge myself on the Athenians!’ After this speech, he bade one of his servants every day, when his dinner was spread, three times repeat these words to him, ‘Master, remember the Athenians.’”
The city of Miletos and the island of Samos were totally destroyed, all the men killed and women and children sold into slavery

The First Persian War 492-90 B.C.

Darius did not personally lead an invasion against Greece. His generals, Datis (a Mede), and Artaphernes, his nephew, led the expedition.
There was an earlier and unsuccessful attempt to invade Greece led by Mardonius, Darius’ son-in-law, that floundered off Mt. Athos.
The Persian army was assisted by an Athenian traitor, Hippias, the son of the tyrant, Peisistratus.
The climactic battle of the First Persian War was at Marathon:
The Athenians were led by Miltiades.
The Olympic victor in the stade (the sprint), Philippides, ran to Sparta to ask their help in the battle. They refused because the moon was not yet full. Philippides ran back to Marathon in time to fight in the battle.
Then, Philippides ran to Athens to announce the victory at Marathon, collapsing and dying after gasping out “We have won.” The modern marathon race is named after his achievement.

Family

Father of three sons, including first-born son, Artabazanes, by first wife, daughter of Gobryas.
Father of four children by Atossa, daughter of Cyrus the Great. His eldest son by her was Xerxes.
Darius died a natural death after ruling Persia for thirty-six years. When he died he was preparing an invasion of Greece to avenge the loss at Marathon