The old Louvre architecture in seen here through I.M. Pei's new glass pyramid entrance.
The Louvre was a defensive fortress on the Seine in the 12th c, transformed into a royal residence in the 14th c.
It was a Renaissance palace for Francis I, and remained so until Louis XIV moved the court to Versaille in 1678.
The Louvre became a "museum for the people" at the time of the French Revolution in 1793.
The Grand Louvre we see today is the culmination of centuries of history, additions and modifications.