The Siam that Chulalongkorn inherited was a kingdom of tributary centres rather than a bounded state, and its monastic order matched that shape. Lineages in the north, the northeast and the peninsula ordained on their own authority, followed their own reading of the discipline, and answered to local abbots and local rulers rather than to Bangkok. As the crown replaced tributary relationships with provinces, salaried officials and surveyed borders, the monastic order was one of the few institutions still organized on the old pattern, and it reached into every village in a way the new bureaucracy did not yet.
The Act of 1902 resolved that by absorbing the order into the shape of the state. It placed a supreme patriarch at the head of a hierarchy running down through regional and provincial ecclesiastical officers to the abbot of each monastery, made appointments at every level subject to royal approval, and gave the hierarchy statutory authority over ordination, property and discipline. It also recognized two lawful fraternities within the order, the older Mahanikai and the Thammayut reform movement founded by the king's father, thereby freezing a distinction that had been informal.
The reasoning was not only administrative. A single order teaching a single standard curriculum in a single language was a way of making Siamese subjects out of Lao, Khmer, Malay and northern Tai populations who had recently owed allegiance elsewhere. Monastic schooling became, for several decades, the closest thing the kingdom had to universal education, and it taught a Buddhism defined in Bangkok. Later Thai governments of every kind have used the structure the Act created, which is why arguments about the appointment of the supreme patriarch remain political arguments in Thailand.