Almanac: St. Patrick's Day

(CBS News) And now a page from our "Sunday Morning" Almanac: March 17th, 460, 1,553 years ago today, the earliest year conflicting sources give for the death of Saint Patrick, the patron saint of Ireland.

Born in Britain, Patrick wrote that he was taken away by Irish kidnappers at the age of 16.

After six years of slavery, he escaped from Ireland, studied in monasteries abroad, and eventually returned to Ireland to win Christian converts.

Tradition says Patrick used the three-leaf shamrock to illustrate the Holy Trinity.

And, folklore credits him with driving the snakes out of Ireland.

Though much about St. Patrick's life and ministry remain uncertain, there's no doubting the enthusiasm with which his day, March 17th, is celebrated . . . both in Ireland and around the world.

New York City held America's first St. Patrick's Day celebration back in 1762 -- a tradition it carried on with a huge parade up Fifth Avenue yesterday (one day early because the 17th falls on Sunday).

Chicago also held its party yesterday, featuring a parade through Grant Park . . . and the dying of the Chicago River Kelly green.

Countless other American communities celebrate as well, including tiny Enterprise, Ala., which our Bill Geist visited back in 2006. The town lays claims to the SMALLEST parade . . . just one LONE marcher . . . a tradition begun by the late Patrick John Michael Donohue:

"Me name is Patrick Donahue,
I'm the leader of the band.
We may be small in numbers,
but we're the finest in the land."

Not so small in numbers, really. According to the Census Bureau, 34.5 million Americans trace their ancestry back to Ireland.