Son of Bimbisāra, King of Māgadha, and therefore half-brother to Abhayarājakumāra. He murdered his father to gain the throne, and conspired with Devadatta to kill the Buddha, but was later converted. He had a son Udāyibhadda. DN.i.50

Ajātasattu was greatly impressed by Devadatta’s powers of iddhi and became his devoted follower. Vin.ii.185 He built for him a monastery at Gayāsīsa and waited upon him morning and evening carrying food for him, sometimes as much as five hundred cartloads in five hundred cooking pans. SN.ii.242

Devadatta incited him to seize the throne, killing his father if necessary. When Bimbisāra learnt of the prince’s intentions he abdicated in his favour. But Devadatta was not satisfied till Bimbisāra, who was one of the Buddha’s foremost supporters, was killed.

Ajātasattu helped Devadatta in several of the latter’s attempts to kill the Buddha.

Later he was filled with remorse for these past misdeeds as he confesses himself; DN.i.85 but evidently, for very shame, he refrained from visiting the Buddha till he was won over by the persuasions of his physician Jīvaka Komārabhacca. And when in the end he did go to the Buddha, it was in great fear and trembling; so nervous was he that he imagined conspirators in the very silence surrounding the Buddha where he dwelt in the monastery, in Jīvaka’s Mango grove at Rājagaha. DN.i.49–50

It was on the occasion of this visit that the Sāmaññaphala Sutta was preached. The king admits that he had been to various teachers before, but had failed to find satisfaction in their teachings. It is noteworthy that the Buddha greets the king cordially on his arrival and makes no mention whatever of the king’s impiety. Instead, when Ajātasattu expresses his repentance at the end of the discourse, the Buddha accepts his confession and lets him off almost too lightly. But after the king had departed the Buddha tells the monks how the king’s misdeeds had wrought his undoing both in this world and the next, for if he had not been guilty of them, the Eye of Truth would have been opened for him on the occasion of this sermon. DN.i.85–86

Henceforth the king became a loyal adherent of the Buddha’s faith, though, as far as we know, he never waited again either upon the Buddha or upon any member of the Order for the discussion of ethical matters. He was so full of love and respect for the Buddha that when he heard of Upaka Maṇḍikāputta having spoken rather impolitely to the Buddha, he at once flew into a rage. AN.ii.182

Bimbisāra had married a sister of Pasenadi, and when he was killed she died of grief.

The revenue of a Kāsī village had been given to her by her father, Mahākosala, as part of her dowry, but after Bimbisāra’s murder, Pasenadi refused to continue it. Thereupon Ajātasattu declared war on his uncle. Before this, uncle and nephew seem to have been on very friendly terms. Once Ajātasattu sent Pasenadi a wonderful piece of foreign fabric, sixteen cubits long and eight broad, mounted on a pole to serve as a canopy. This Pasenadi gave to Ānanda. MN.ii.116

At first he was victorious in three battles, but, later, he was defeated by Pasenadi, who followed the military advice of an old monk, the Elder Dhanuggahatissa; Ajātasattu was taken captive with his army. On giving an undertaking not to resort to violence again, he was released, and to seal the friendship, Pasenadi gave him his daughter Vajirā as wife, and the revenue of the disputed village was gifted to her as bath-money. SN.i.82–85

Later, when through the treachery of Pasenadi’s minister, Dīgha Kārāyana, his son Viḍūḍabha usurped the throne, Pasenadi, finding himself deserted, went towards Rājagaha to seek Ajātasattu’s help, but on the way he died of exposure and Ajātasattu gave him burial.

About a year before the Buddha’s death, Ajātasattu sent his chief minister and confidant, the brahmin Vassakāra, to the Buddha to intimate to him his desire to make war on the Vajjians and to find out what prediction the Buddha would make regarding his chances of victory. The Buddha informed the brahmin that the Vajjians practised the seven conditions of welfare which they had learnt from him, and that they were therefore invincible. DN.ii.72f. The Saṃyutta Nikāya mentions the Buddha as saying that the time would come when the Vajjians would relinquish their strenuous mode of living and that then would come Ajātasattu’s chance. SN.ii.268

Rumours are mentioned of King Candappajjota making preparations for a war on Ajātasattu to avenge the death of his friend Bimbisāra, but no mention is made of actual fighting. MN.iii.7

It was he who built the fortress of Pāṭāliputta, which later became the capital of Māgadha.