Cyrus Reign and successor

 

After Cyrus the Great, his son 

Cambyses II ruled the Persian Empire (530-522 BCE) and conquered Egypt, but after his death, there was a brief succession crisis before Darius the Great (Darius I) took power, established stability, and significantly reorganized the empire through administrative reforms and infrastructure, becoming a pivotal ruler. 

The Succession After Cyrus the Great:

1. Cambyses II (Son of Cyrus): Succeeded his father, expanding the empire by conquering Egypt. He died around 522 BCE.
2. Bardiya/Gaumata (Usurper): Following Cambyses' death, a figure named Bardiya briefly claimed the throne before being overthrown.
3. Darius I (Darius the Great): Emerged victorious from the power struggle, becoming the next great ruler of the Achaemenid Empire, known for his administrative genius. 

Key Rulers Following Darius I:

• Xerxes I: Darius's son, known for his massive invasion of Greece.
• Artaxerxes I, Darius II, Artaxerxes II, Artaxerxes III: A succession of rulers who maintained the vast empire, as detailed on this Quora page. 

Artaxerxes I was the fifth King of Kings of the Achaemenid Empire, from August 465 to December 424 BC. He was the third son of Xerxes I.

In short, while Cambyses II came immediately after Cyrus, Darius I established the lasting structure of the empire after a brief period of turmoil, with Darius I and Darius the Greatbeing major figures in the dynasty's history. 

After Artaxerxes I, the Achaemenid throne saw a succession of short, tumultuous reigns: his legitimate son Xerxes II (45 days) was assassinated by his half-brother Sogdianus, who was then overthrown by Darius II (Ochus), who ruled for about 19 years. Darius II was followed by Artaxerxes II. 

Here's a breakdown of the immediate successors:

• Xerxes II: Artaxerxes I's only legitimate son, he ruled for only 45 days in 424 BC before being murdered.
• Sogdianus: An illegitimate son of Artaxerxes I, he seized the throne from Xerxes II but was himself murdered after about a month.
• Darius II (Ochus): Another illegitimate son, he took power from Sogdianus in 423 BC and ruled until 404 BC.
• Artaxerxes II (Mnemon): Succeeded Darius II, beginning a long reign in 404 BC.