The chapel was one of Louis XIV's final projects at Versailles.
However he only had the opportunity to use it for 5 years before his death.
The king would attend mass here every day.
He would sit on the upper level - beneath a painting of himself in full battle gear!
He would only go downstairs for special celebrations.
The chapel was dedicated to both himself and Saint Louis - the patron saint of the Bourbon monarchy.
The Bourbon dynasty was one of Europe's oldest ruling families - ruling almost continuously from 987 to 1848.
Indeed, the Capetian dynasty, founded by Hugh Capet and including Saint Louis (Louis IX), ruled from 987 to 1328.
The Valois, a branch of the Capetians, succeeded them, ruling from 1328 to 1589.
The Bourbons, another Capetian branch, began their rule with Henry IV in 1589 and continued until 1848.
The two Ls near the altar symbolize both Louis XIV and Saint Louis.