Which early ruler of Magadha murdered his own father to ascend the throne and was later murdered by his own son, creating a tragic cycle of patricide and revenge in the royal family?

Introduction / Context:
The early history of Magadha is full of dramatic events involving royal power struggles. One tragic episode involves a ruler who seized the throne by killing his own father and was later killed by his own son. This story shows how succession conflicts could turn violent in ancient Indian monarchies. The question asks you to identify this ruler, which is a common fact tested in ancient Indian history sections of exams.

Given Data / Assumptions:
• The setting is early Magadha, an important kingdom in ancient north India. • The ruler in question killed his father to become king. • He was later murdered by his own son, completing a cycle of patricide. • The options include Bimbisar, Ajatasatru, Udayan and Nagadashak.

Concept / Approach:
Bimbisara was a powerful ruler of Magadha and a contemporary of the Buddha. His son Ajatasatru is widely known in Buddhist and Jain texts for imprisoning and ultimately causing the death of his father to seize power. Later traditions state that Ajatasatru himself was murdered by his son Udayin or Udayabhadra. This means Ajatasatru both killed his father and was in turn killed by his son. The other rulers listed do not match both parts of this pattern together.

Step-by-Step Solution:
1. Recall that Bimbisara was a king of Magadha who expanded the kingdom through marriages and conquests. 2. Remember that his son Ajatasatru, influenced by ambition and perhaps external advisors, rebelled against Bimbisara. 3. Traditional accounts suggest that Ajatasatru imprisoned his father and caused his death, effectively murdering him to gain the throne. 4. Later, the same sources mention that Ajatasatru was himself murdered by his son Udayin, creating a cycle of violence in the royal family. 5. Check the options against this narrative: Ajatasatru is the one who fits both conditions, not Bimbisara, Udayan or Nagadashak. 6. Therefore the correct answer is Ajatasatru.

Verification / Alternative check:
Buddhist and Jain texts such as the Buddhist chronicles refer to Ajatasatru as the son who killed or caused the death of Bimbisara. They also narrate how Ajatasatru later regretted his actions and turned to the Buddha for guidance. Historical summaries of Magadha early history confirm that Ajatasatru was eventually killed by his own son, which reinforces his identification as the ruler described in the question.

Why Other Options Are Wrong:
Bimbisar: He was the victim in this story, killed by his son Ajatasatru, rather than the murderer of his own father. Udayan: Also written as Udayin, he is described as the son who killed Ajatasatru, not the ruler who both killed his father and was killed by his son. Nagadashak: A later ruler of the Haryanka dynasty with no widely known story matching this exact pattern of patricide and retaliation.

Common Pitfalls:
Students sometimes confuse which member of the family committed which act, especially because names like Udayin and Ajatasatru can be less familiar. Another mistake is to select Bimbisara because he is the more famous early ruler, forgetting that he was the victim, not the perpetrator. Keeping the simple chain in mind helps: Bimbisara was killed by Ajatasatru, and Ajatasatru was killed by his own son Udayin. Thus Ajatasatru is the ruler who both murdered his father and was later murdered by his son.

Final Answer:
The early ruler of Magadha who killed his father and was later killed by his own son was Ajatasatru.