Explanation:

• Ajatashatru (Ajatsattu) was a king of the Haryanka dynasty of Magadha in North India.
• He was the son of King Bimbisara and was a contemporary of both Mahavira and Gautama Buddha.
• He forcefully took over the kingdom of Magadha from his father and imprisoned him.
• He fought a war against Vajji, ruled by the Lichchhavis, and conquered the republic of Vaishali.
• Ajatashatru followed policies of conquest and expansion.
• He defeated his neighbours including the king of Kosala; his brothers, when at odds with him, went to Kashi, which had been given to Bimbisara as dowry.
• This led to a war between Magadha and Kosala.
• Ajatashatru occupied Kashi and captured the smaller kingdoms.
• Magadha under Ajatashatru became the most powerful kingdom in North India.
• Ajatashatru, with the help of his two ministers Sunidha and Vassakara, built a fort near the banks of the river Ganges to strengthen the defense of Magadha and named it Patali Grama(village).
• Later it developed into a city, which soon became popular as Pataliputra, now known as Patna, the capital of Bihar.