Pius X (#258), on May 29, 1954, was the last pope, to date, to be canonized.
Prior to Pius X, it had been Pius V (#226) in May 1712 — 242 years separating these two canonizations. You have to go back another 399 years from Pius V, to May 1313, for the previous pope to canonized, that being Celestine V (#193), the ‘God-Father’ of today’s papal conclaves.
The table below charts the time-line for the Pius X canonization, which took close to 40 years, and shows how the time taken for his canonization process compares with those of others:
<< click on table to get a larger image >>
The canonization of Pius V took considerably longer, while that of Celestine V, in the 14th century, took less than half the time. As far as I am concerned, Celestine deserved to be canonized, if nothing else, for institutionalizing papal conclaves — in the ardent hope that they would expedite papal election. His piety, he having been a well known hermit monk, is also beyond reproach. It is thus rather unfortunate that there is a belief that his canonization was due to imperial coercion by Philip IV of France — who apparently wanted Celestine canonized so as to disparage Celestine successor Boniface VIII (#194)!
The beatification/canonization processes of John Paul II (#265) and Mother Teresa of Calcutta were ‘fast tracked’ — i.e., the 5 year waiting period prior to the process being initiated was waived by a pope. Mother Teresa’s beatification, in 2003, did occur very quickly. It is possible that she could gain her sainthood in less time than it took Celestine.
It is interesting to note that Pius X and John XXIII (#262) were beatified in more or less the same time. However, Pius canonization occurred very soon after that.
Study the table. It is interesting. Hope you like it.