It is clear that, though the Hinayanist church was predominant throughout the history of the island, there were up to the twelfth century heretical sects called Vaitulya or Vetulyaka and Vajira which though hardly rivals of orthodoxy were a thorn in its side.  A party at the Abhayagiri monastery were favourably disposed to the Vaitulya sect which, though often suppressed, recovered and reappeared, being apparently reinforced from India.  This need not mean from southern India, for Ceylon had regular intercourse with the north and perhaps the Vaitulyas were Mahayanists from Bengal.  The Nikaya-Sangrahawa also mentions that in the ninth century there was a sect called Nilapatadarsana,[106] who wore blue robes and preached indulgence in wine and love.  They were possibly Tantrists from the north but were persecuted in southern India and never influential in Ceylon.

The Mahavamsa is inclined to minimize the importance of all sects compared with the Mahavihara, but the picture given by the Nikaya-Sangrahawa may be more correct.  It says that the Vaitulyas, described as infidel Brahmans who had composed a Pitaka of their own, made four attempts to obtain a footing at the Abhayagiri monastery.[107] In the ninth century it represents king Matvalasen as having to fly because he had embraced the false doctrine of the Vajiras.  These are mentioned in another passage in connection with the Vaitulyas:  they are said to have composed the Gudha Vinaya[108] and many Tantras.  They perhaps were connected with the Vajrayana, a phase of Tantric Buddhism.  But a few years later king Mungayinsen set the church in order.  He recognized the three orthodox schools or nikayas called Theriya, Dhammaruci and Sagaliya but proscribed the others and set guards on the coast to prevent the importation of heresy.  Nevertheless the Vajiriya and Vaitulya doctrines were secretly practised.  An inscription in Sanskrit found at the Jetavana and attributed to the ninth century[109] records the foundation of a Vihara for a hundred resident monks, 25 from each of the four nikayas, which it appears to regard as equivalent.  But in 1165 the great Parakrama Bahu held a synod to restore unity in the church.  As a result, all Nikayas (even the Dhammaruci) which did not conform to the Mahavihara were suppressed[110] and we hear no more of the Vaitulyas and Vajiriyas.

Thus there was once a Mahayanist faction in Ceylon, but it was recruited from abroad, intermittent in activity and was finally defeated, whereas the Hinayanist tradition was national and continuous.

Considering the long lapse of time, the monastic life of Ceylon has not deviated much in practice from the injunctions of the Vinaya.  Monasteries like those of Anuradhapura, which are said to have contained thousands of monks, no longer exist.  The largest now to be found—­those at Kandy—­do not contain more than fifty but as a rule a pansala (as these institutions are now called) has not more than five residents and more often only two or three.