Burma became independent in 1948 and within a few years its government was preparing a Buddhist council. The first council, in the tradition's account, had met in a cave outside Rajagriha, so a cave was built: the Maha Pasana Guha at Yangon, an artificial hall in the shape of a cavern, large enough to seat a very large assembly of monks.
The work took from 1954 to 1956 and drew participants from Burma, Sri Lanka, Thailand, Cambodia, Laos and India. The task was collation. Each of those countries had a printed edition of the Pali canon in its own script, produced from its own manuscript lineage, and the editions did not agree everywhere. Section by section the assembly compared them, settled readings and approved a text, together with the commentaries and the sub-commentaries, which no previous council had attempted at that scale.
The timing was chosen. The council closed in 1956, on the traditional two thousand five hundredth anniversary of the Buddha's final passing, a date freighted in Theravada Asia with expectations about the state of the teaching at the halfway point of its predicted lifespan. A state four years old was placing itself at the centre of that moment.
Reading the political intention and the scholarly work as competing explanations would be a mistake. The government wanted the prestige; the monks who did the collating wanted an accurate text; and both got what they wanted from the same event, which is how most councils in most traditions have actually worked.