Spreading the change over 40 years ran the risk of having a new pope reversing the decision. Sweden tried to do it this way and failed.[1] I would also suspec

Spreading the change over 40 years ran the risk of having a new pope reversing the decision. Sweden tried to do it this way and failed.[1] I would also suspect that vanity played some role. If you start the slow transition you don't get a new calendar named after you. [1] http://en.wikipedia.org/wiki/February_30#Swedish_calendar http://en.wikipedia.org/wiki/February_30#Swedish_calendar