Artabanus' group

In the first half of the 5th century BCE, a group of Persian freedom fighters led by Darius (formerly known as Artabanus) opposed the secret rule of the Order of the Ancients. The group gathered with the goal of dismantling the rule of King Xerxes, an ally of the Ancients. It is one of the precursor groups of what would become known as the Assassin Brotherhood.

History
In August 465 BCE, the group, including Amorges and Pactyas, ambushed Xerxes and his entourage while en route in Persia, killing his guards. While they took down Xerxes' guards, Darius, who worked as Xerxes' personal guard, killed the King using a Hidden Blade he had created – this would become the first assassination using the Hidden Blade, centuries before it became the Assassins' primary weapon.

After Xerxes' death, Darius sought to prevent the Order of the Ancients from exerting their influence of the king's successor, the young Artaxerxes, and planned to kill him. He faced opposition from Amorges, who instead persuaded the rest of the group to join forces with the Ancients, to use their resources for create a better future for Persia. Darius made another attempt on Artaxerxes life using poison, which only left the young king blind, before spending the next decades being pursued by his former allies.

For its parallels with the later Assassin Brotherhood, the group later came to be seen by the Assassins as one of their antecedents and dubbed the Persian Brotherhood, with Darius being honored posthumously as one of their legendary predecessors.