When the Buddha was alive there was no chanting, no ritual and ceremony, only meditation. There was no Uposatha (consecrated assembly hall), Sala (pavilion), Kuti (living hall for monks), or Vihara (shrine hall). Though there were 3000 monks, there was still no temple. Those monks lived and practised under trees, in caves, and in the forest. Three thousand monks is a great number compared with less than 1000 at Wat Sanghathan. Even a congregation of 200 lay people is considered quite a number nowadays.
In the early days of the Order monks lived close to nature. The ordination did not require an Uposatha, only the Buddha’s mere utterance, “Ehi Bhikkhu Upasampada” (“Come, Monks!, well taught is the doctrine; lead the Holy Life to make a complete end of suffering.”) With these words the Buddha conferred the ordination.
Those lay men automatically became monks. Thousands of them were ordained at the same time.
Those monks knew all about the Dhamma and could teach ‘Panja kammathana’ (The five meditation exercises): namely, the hair on the head, the hair on the body, the nails, the teeth and the skin. They became preceptors and teachers in different countries.
As they knew how to meditate, Buddhism became very prosperous during that time. Eight years after his Enlightenment, the Buddha did not have a temple. When he went to Rajagaha, King Bimbisara offered him the first temple with Sala, Kuti and Vihara. There was no record about building an Uposatha. There was no building of an Uposatha, no ceremony of lifting the roof spiral during the Buddha’s time. Building the Vihara, Kuti, well and road were considered meritorious deeds.
The idea that one gained merit from building the Uposatha might have started after the Sukhothai or Ayudhaya periods, while building the Vihara was considered the important thing before. Nowadays the Vihara does not have the same significance because it is just a place for keeping Buddha images and the Tepitaka (Scriptures). In the early period, it was the place where monks used to take precepts and meditate, and were diligent. So when he was alive, the Buddha showed his followers where the temple was – in his own mind.