In ancient Magadhan history, which ruler is generally credited with choosing Pataliputra (near modern Patna) for the first time as the capital city of his kingdom?

Introduction / Context:
This question is about the early political development of Magadha, a powerful kingdom in ancient India. The shift of the capital to Pataliputra (near present-day Patna) was a crucial step in Magadha's rise as an imperial power, later becoming the capital of the Mauryas and others. Knowing which early ruler first chose Pataliputra as his capital helps you understand the geographic strategy behind Magadha's expansion.

Given Data / Assumptions:

• The focus is on the first time Pataliputra was selected as a capital.
• We are dealing with early Magadhan rulers.
• Options given: Ajatasatru, Udayin, Kalasoka, Kanishka.
• We assume standard ancient Indian history chronology.

Concept / Approach:
Ajatasatru expanded Magadha's territory and is associated with Rajagriha (Rajgir). His son Udayin (or Udayabhadra) is generally credited with founding Pataliputra at the confluence of the Ganga and Son rivers and shifting the capital there to take advantage of its strategic riverine location. Kalasoka was a later Shishunaga ruler associated with the second Buddhist council. Kanishka was a much later Kushana ruler unrelated to Magadha's early capital shift. Therefore, Udayin is the ruler who first made Pataliputra the capital.

Step-by-Step Solution:
Step 1: Recall the succession: Bimbisara → Ajatasatru → Udayin in the Haryanka dynasty of Magadha. Step 2: Note that Ajatasatru strengthened Rajagriha but did not permanently shift the capital to Pataliputra. Step 3: Remember that Udayin founded Pataliputra and moved the capital there due to its strategic riverside location. Step 4: Recognise that Kalasoka and Kanishka belong to different dynasties and periods. Step 5: Select Udayin as the correct answer.

Verification / Alternative check:
Standard history texts on the Magadhan empire usually present Pataliputra's origin story under Udayin. They highlight that Pataliputra's placement at a river junction gave it natural defensive advantages and facilitated trade. Ajatasatru certainly fortified Pataligrama (the earlier settlement), but the honour of making it a full-fledged capital is generally attributed to Udayin. Kalasoka’s reign and Kanishka’s empire lie outside this context, which confirms our choice.

Why Other Options Are Wrong:
Option a (Ajatasatru) did play a role in fortifying Pataligrama but is not usually credited with formally making Pataliputra the capital. Option c (Kalasoka) was a later ruler of the Shishunaga dynasty and is better known for his association with the second Buddhist council. Option d (Kanishka) was a Kushana ruler, much later and geographically centred in northwestern India, not Magadha, so he could not have made Pataliputra the first capital of Magadha.

Common Pitfalls:
Students often confuse the roles of Ajatasatru and Udayin because both are linked with early development of Pataliputra. Some sources emphasise Ajatasatru’s fortifications, which may tempt you to choose him under exam pressure. To avoid this, remember a clear division: Ajatasatru fortifies Pataligrama, Udayin founds Pataliputra and shifts the capital there. Fixing this sequence in your mind will help you answer related questions correctly.

Final Answer:
Udayin is generally credited with choosing Pataliputra as the capital of Magadha for the first time.