Article: Napoleon turned his focus to domestic affairs after the war. Empress Josephine had still not given birth to a child from Napoleon, who became worried about the future of his empire following his death. Desperate for a legitimate heir, Napoleon divorced Josephine in January 1810 and started looking for a new wife. Hoping to cement the recent alliance with Austria through a family connection, Napoleon married the Archduchess Marie Louise, who was 18 years old at the time. On 20 March 1811, Marie Louise gave birth to a baby boy, whom Napoleon made heir apparent and bestowed the title of King of Rome. His son never actually ruled the empire, but historians still refer to him as Napoleon II.

Question: When did Marie Louise give birth?
20 March 1811