[2][3] He is seen as the defender of the true teaching or Dhamma against corruption, during a time where many kinds of wrong view had arisen and as the force behind the Ashokan era Buddhist missionary efforts.
[5] He also seems to have been a staunch critic of certain Buddhist doctrinal views, mainly Sarvāstivāda (an eternalist theory of time), Pudgalavāda ("personalism") and Lokottaravāda ("transcendentalism").
Bhante Sujato, in his study of the Buddhist sectarian literature, notes how the passages depicting the Third council in the Sudassanavinayavibhāsā does not mention the compilation of the Kathāvatthu by Moggaliputtatissa, but that later works such as the Samantapāsādikā and Kathāvatthu-aṭṭhakathā add this attribution.
Nevertheless: ...there is no reason why the core of the book should not have been started in Aśoka's time, and indeed K. R. Norman has shown that particularly the early chapters have a fair number of Magadhin grammatical forms, which are suggestive of an Aśokan provenance.
So it is possible that the main arguments on the important doctrinal issues, which tend to be at the start of the book, were developed by Moggaliputtatissa and the work was elaborated later.
Rather than seeing the story of Upagupta as somehow corroborative evidence that Moggaliputta Tissa was associated with Asoka in the manner described in the Samantapāsādikā, it seems more reasonable to see the details of the stories that associate figures such as Moggaliputta Tissa, Upagupta and Mahinda with Asoka as part of a more general strategy to enhance the reputation and prestige of these teachers and their lineages.
According to the Mahavamsa, Tissa, who was thoroughly proficient, at a young age was sought after by the Buddhist monks Siggava and Candavajji for conversion, as they went on their daily alms round.
According to the Samantapāsādikā, due to the great wealth which accrued to the sangha through Ashoka's patronage, many non-buddhist ascetics (titthiyas) joined the order or began to dress and act like Buddhists.
Because of this, the formal acts of the sangha (sanghakamma) were compromised and monks did not feel they were able to carry out the uposatha ceremony which was thus suspended for a period of seven years at the Aśokārāma.
[5] Moggaliputtatissa is then said to have compiled the Kathavatthu, in refutation of various wrong views held by the expelled ascetics, and it was in this council that this text was approved and added to the Abhidhamma.