Which ruler of Magadha was the contemporary of Alexander the Great during his invasion of northwestern India in the 4th century BC?

Introduction / Context:
Alexander the Great invaded northwestern India around 326 BC. At that time, Magadha in eastern India was already a powerful kingdom. Knowing which ruler sat on the Magadhan throne when Alexander arrived is a frequent exam question, because it links Greek and Indian chronologies and sets the stage for the later rise of the Mauryan Empire.

Given Data / Assumptions:

• The time frame is the invasion of Alexander the Great (4th century BC).
• The kingdom in question is Magadha.
• The options list Mahapadma Nanda, Dhanananda, Sukalp, and Chandragupta Maurya.
• We assume that the learner knows Alexander did not directly fight the Magadhan king but that his presence influenced later events.

Concept / Approach:
Traditional accounts and many historical reconstructions suggest that the last Nanda ruler, often identified as Dhanananda, was ruling Magadha when Alexander invaded the northwestern frontiers of the Indian subcontinent. Mahapadma Nanda is usually regarded as the founder of the Nanda dynasty, ruling earlier than Alexander's incursion. Chandragupta Maurya rose to power shortly after Alexander's departure, overthrowing the Nanda rule. The name Sukalp is not a standard name associated with Magadhan kings in this context. Thus, the king contemporary with Alexander is Dhanananda.

Step-by-Step Solution:
Step 1: Place Alexander's Indian campaign around 326 BC in the late 4th century BC. Step 2: Recall that the Nanda dynasty ruled Magadha just before the Mauryan dynasty. Step 3: Recognise that Mahapadma Nanda founded the Nanda line, while Dhanananda is usually considered its last ruler. Step 4: Remember that Chandragupta Maurya overthrew Dhanananda soon after Alexander's invasion and withdrawal. Step 5: Note that “Sukalp” is not widely listed as a Magadhan king in standard exam syllabi. Step 6: Conclude that Dhanananda was ruling Magadha when Alexander entered northwestern India.

Verification / Alternative check:
History textbooks that discuss Alexander's invasion often mention that the powerful Nanda king in distant Magadha discouraged Alexander's weary troops from advancing further east. They frequently name this king as Dhanananda. Later, narratives about Chanakya and Chandragupta Maurya describe how Chandragupta defeated this last Nanda ruler. Together, these accounts strongly support Dhanananda as Alexander's contemporary in Magadha.

Why Other Options Are Wrong:

• Mahapadma Nanda: The founder of the Nanda dynasty who ruled earlier than the time of Alexander's campaign.
• Sukalp: Not recognised as a Magadhan king in mainstream historical lists relevant to this period.
• Chandragupta Maurya: He came to power shortly after Alexander's time, overthrowing Dhanananda, so he was not yet ruling Magadha during Alexander's invasion.

Common Pitfalls:
Many students incorrectly choose Chandragupta Maurya because of his fame and his connection to the aftermath of Alexander's invasion. Others may confuse the founder and the last ruler of the Nanda dynasty, mixing up Mahapadma Nanda and Dhanananda. To avoid this, remember the sequence: Mahapadma Nanda founded the dynasty, Dhanananda ruled at the time of Alexander, and Chandragupta Maurya later overthrew Dhanananda to begin the Mauryan Empire.

Final Answer:
The ruler of Magadha who was contemporary with Alexander the Great was Dhanananda.