In ancient Magadhan history, Ajatashatru was the son of which ruler?

Introduction / Context:
Ajatashatru was one of the important kings of ancient Magadha and played a significant role in the expansion of the Magadhan empire. He appears in both Buddhist and Jain traditions and is linked to the time of the Buddha and Mahavira. To correctly place him in the Magadhan royal lineage, it is important to know which earlier king he was the son of.

Given Data / Assumptions:

• The question asks specifically about the father of Ajatashatru.
• The options given are Brahmadatta, Bindusara, Bimbisara, Chetaka and Udayin.
• We must know the sequence of Magadhan rulers in the Haryanka dynasty and distinguish them from rulers of later dynasties like the Mauryas.

Concept / Approach:
Ajatashatru belonged to the Haryanka dynasty of Magadha. His father was King Bimbisara, who greatly expanded Magadha's power and is frequently mentioned in Buddhist texts. Ajatashatru is said to have imprisoned, and in some accounts killed, his own father to seize the throne. Bindusara, by contrast, was the father of the Mauryan emperor Ashoka and lived much later. Brahmadatta and Chetaka belong to other regional traditions, and Udayin is usually described as Ajatashatru's successor, not his father.

Step-by-Step Solution:

Verification / Alternative check:
Standard histories of ancient India, as well as Buddhist texts such as the Pali sources, describe Bimbisara as the father of Ajatashatru. They narrate how Ajatashatru's usurpation and Bimbisara's tragic end mark a turning point in Magadhan politics. No credible source treats Bindusara, Brahmadatta or Chetaka as his father. This unanimity confirms that Bimbisara is the correct response.

Why Other Options Are Wrong:

• Brahmadatta: Used as a name for various kings in North Indian lore, but not identified as Ajatashatru's father in Magadhan history.
• Bindusara: A Mauryan king, son of Chandragupta Maurya and father of Ashoka, living centuries after the Haryanka rulers.
• Chetaka: Famous as a Licchavi leader and associated with Jain traditions, not as a Magadhan king.
• Udayin: Generally regarded as the son and successor of Ajatashatru, not his father.

Common Pitfalls:
Students frequently confuse Bindusara with Bimbisara because of the similarity in their names, and also mix up the Haryanka and Mauryan dynasties. An easy way to remember is: Bimbisara–Ajatashatru–Udayin (Haryanka line) come well before the sequence Chandragupta–Bindusara–Ashoka (Mauryan line). Keeping these family chains separate prevents errors.

Final Answer:
Correct answer: Bimbisara.