Have you ever wondered where the idea of retirement at the age of 65 came from? I'll tell you where: Otto von Bismarck, the president of Prussia, in 1889. Actually, Bismarck's government: At the time, the life expectancy of the average Prussian was about 45. Today, so many are living well into their 80s and 90s that the same promise might well bankrupt the federal government within the next generation.