Nevertheless, I think this event must be placed after Aśoka. Such a mass of authority cannot be discarded lightly, and I should probably try to explain why I have come to such different conclusions.
The texts as we have them ascribe the schisms to one of three periods relative to Aśoka: before (Dīpavaṁsa and Bhavya III), during (Vasumitra and probably the Sarvāstivāda generally), or after (Śāriputraparipṛcchā). I have not seen an explicit rationale for exactly why the root schism must be pre-Aśokan, but the reasoning must go something like this.
Two sources place the schisms before Aśoka. This includes the Sinhalese tradition, which is more historically reliable. Vasumitra places events in the time of Aśoka, but this is a short chronology text. The calendar date of the schism according to Vasumitra is about 100 A.N. This roughly agrees in years with the Dīpavaṁsa (100+ A.N.) and Bhavya III (137 A.N.). Vasumitra, therefore, has the date approximately right, but following the tradition of his school, he thinks that this was the reign of Aśoka. Apparently this tradition confuses the ‘Kāḷaśoka’ of the Second Council with the famous ‘Dharmāśoka’. The Śāriputraparipṛcchā is closely related to this tradition, but in placing the schism later has become confused in its chronology. The ‘Schism edicts’ indicate that either Aśoka was not fully aware of what was going on – which we know is sometimes the case – or that he is referring to a mere party dispute among the Theravādins.
We have already demonstrated some of the problems with this reasoning. The Dīpavaṁsa should be entirely disregarded in this matter. Bhavya III is late, unsupported, and polemical. Unfortunately, we know little of the Puggalavāda mythos, and so cannot interpret what meaning this story had. But we may be confident that, like all the other versions, it must have served the purpose of archaic legitimation of the communal identity of the Puggalavāda.
Vasumitra is speaking in the same tradition as the Mahāvibhāṣā, and although the Mahāvibhāṣā does not mention the King’s name, we should see these sources as representing the same mythos. The events happened under a pious Buddhist king of Pāṭaliputta who sponsored the Kaśmīr mission. The purpose of the myth is to associate the Sarvāstivādins of Kaśmīr with the root-Sthaviras in the time of Aśoka. The calendar date is irrelevant to this mythos, and has merely been inserted to give historical fixity to an event which, from Vasumitra’s point of view, must have happened around that time.
For similar reasons, we cannot discount the ‘Unity Edicts’ as being merely Aśoka’s unawareness of what was happening in the Sangha. This argument pivots on an insoluble dilemma. The very same texts that tell us the schism was Aśokan or pre-Aśokan also assert Aśoka’s intimate involvement in the schisms. It is Aśoka’s involvement, not the date, that is the key issue. The date is merely a chronological reconciliation of the events with the general chronology of the different schools. So are we to discard the critical element of Aśokan involvement while accepting the incidental detail of the date? Of course it is possible that Aśoka was not in fact fully aware of what was happening, but if he was unaware, the sources are unreliable.
And regarding the supposed ‘confusion’ of the Śāriputraparipṛcchā, we can only assert that, aside from its obvious mythical nature and several textual problems, it is not confused about its own chronology. The ascription of the schism to a date after Aśoka is no accident, but is inherent in the logic of the text. First it acknowledges the usual five ‘Masters of the Law’, culminating with Upagupta, who is contemporary with Aśoka. Clearly there is no schism so far, as the list of patriarchs is identical with the mainstream (Mūla) Sarvāstivāda tradition. After Aśoka we are told of the persecutions under Puṣyamitra; again, this is entirely in accord with the (Mūla) Sarvāstivāda tradition. The events of the root schism itself are very different from the other accounts, and so while the account of the ‘18 schools’ shares a common basis with Vasumitra, we cannot infer that the account of the root-schism is merely a confusion of Vasumitra.
Lamotte says that this text is: ‘… so obscure that it allows for the most diverse interpretations. After having narrated at length the persecution by the Śuṅga Puṣyamitra, the text, going back to the past, speaks of events which took place under a king whom it does not name, but who, from the evidence of other parallel texts which we shall quote, can be none other than Aśoka the Maurya.’ (Lamotte, 1976, 172) But the text, in this respect at least, is not all all obscure, nor does it hint at a flashback in time, but simply relates a series of consecutive events. I agree with Lamotte that Fa-xiang’s version of events in his postface to the Mahāsaṅghika Vinaya is related to the Śāriputraparipṛcchā, but it seems to me that it is Fa-xiang who, writing at a much later date, has got the chronology confused. He too starts with an evil king who persecutes the bhikkhus; but this must be Puṣyamitra, as there are no known pre-Aśokan persecutions. Then he goes on to relate the story of the king presiding over the vote with tally-sticks; but to the Śāriputraparipṛcchā’s account he adds the anachronistic detail that the king was Aśoka. (Lamotte, 1976, 173)
The first calendar date the text gives us is 300 A.N. for the division of the root-Sthaviras into Sarvāstivāda and Puggalavāda. Assuming the short chronology of the text, this would be roughly 170 years after Aśoka’s death, which again makes perfect sense of the internal chronology. The Mahāsaṅghika schisms, as is generally the case, are said to be earlier than the Sthavira schisms, so they are dated 200 A.N. This brings them, say, 70 years after Aśoka, around 170 B.C.E. Puṣyamitra died around 151 B.C.E., so our dates are about 20 years out. But given that the Śāriputraparipṛcchā speaks in units no smaller than centuries, who’s to worry about a few decades here and there? In any case, this relates to a later portion of the text. Thus we can definitely conclude that the internal chronology of the relevant portions of the Śāriputraparipṛcchā is not confused. It merely disagrees with the chronology of other texts.
Can we say anything else about the chronology of the Śāriputraparipṛcchā? One relevant detail is the interference of the King. This apparently agrees with the Mahāsaṅghika Vinaya. But the Mahāvihāravāsin Vinaya says nothing about royal interference, despite the school’s approval, even celebration, of Aśoka’s interference as establishing the essential model for Sangha-State relations, ensuring the very survival of the Dhamma. Of course the later Mahāvihāravāsin texts assert that Kāḷasoka sponsored the Second Council, and Ajātasattu sponsored the first, but these are just back-readings to authorize Aśoka’s role. Thus such justifications for Royal involvement, while not against the general spirit of Indian legal procedures, must be post-Aśokan. Similarly, the use of tally-sticks to vote in an important procedure is not supported by the Pali Vinaya, although we should not be surprised if the Mahāsaṅghika Vinaya took a different perspective on this. Finally, we note the presence of written texts.
One of the most pervasive motivations in forming mythic texts is to seek archaic authorization for contemporary events, hence the very common mythic tendency to date formative events earlier rather than later. On prima facie expectations, we should expect that the version placing the schism later would be more reasonable. In addition, the Śāriputraparipṛcchā is less polemical than the other versions, indicating a healthier and more realistic attitude towards such things, and consequently fewer motives to twist events to its own perspective. We have also seen that this version is in perfect accord with the epigraphic evidence and with the Mahāvihāra Vinaya commentaries.
 (Bechert, Theravada Buddhist Sangha 3)
 (Bechert, The Date of the Buddha Reconsidered 66)
 (Prebish, Review of Scholarship on Buddhist Councils 237)
 (Cousins, Pali Oral Literature 104)
 (Nattier and Prebish 224)
 E.g. the Kandahar Edicts say that the fishers and hunters had stopped fishing and hunting, which according to Basham is sheer complacency (Basham 59).
 For various versions of this legend, see (Lamotte, History of Indian Buddhism 386-392).
 The lack of mention of Aśoka and royal interference in Sangha affairs is, incidentally, one of the reasons for thinking the Pali Vinaya was fixed relatively early.