Short answers, pulled from the story.
Napoleon issued an oral commission to Jacques-Louis David in September 1804. The official painter of the French Emperor began work on the 21st of December 1805.
The Salon of 1808 displayed the finished work from February 7 to the 22nd of March 1808 at the Louvre. It later entered the decennial prize competition held during the Salon of 1810.
Joséphine de Beauharnais kneels in a submissive position required by the French Civil Code. She receives the crown from her husband rather than from Pope Pius VII.
David placed Napoleon's mother in the stands as a protest against family tensions. An outline of this self-crowning attempt remains visible on the final canvas because Napoleon instructed that the painting should depict him anointing the proceedings instead.
American entrepreneurs commissioned a full-size replica from David in 1808 immediately after the original release. Completion did not occur until 1822 during his exile in Brussels.