The siege of Acre of 1799 was an unsuccessful French siege of the Ottoman city of Acre and was the turning point of Napoleon's invasion of Egypt and Syria, along with the Battle of the Nile. It was Napoleon's third tactical defeat in his career, being defeated at the Second Battle of Bassano and the Battle of Caldiero three years previously during the Italian campaign, and his first major strategic defeat, along with the last time he was defeated in battle for 10 years. As a result of the failed siege, Napoleon Bonaparte retreated two months later and withdrew to Egypt.

Napoleon Bonaparte, later known by his regnal name Napoleon I, was a French emperor and military commander who rose to prominence during the French Revolution and led successful campaigns during the Revolutionary Wars. He was the leader of the French Republic as First Consul from 1799 to 1804, then of the French Empire as Emperor of the French from 1804 until 1814, and briefly again in 1815. His political and cultural legacy endures as a celebrated and controversial leader. He is considered one of the greatest military commanders in history and his wars and campaigns are still studied at military schools worldwide. However, historians still debate the degree to which he was responsible for the Napoleonic Wars, in which between three and six million people died. Napoleon brought modernizing reforms to France and Western Europe and stimulating the development of nation states. He also sold the Louisiana Territory to the United States in 1803, doubling the latter's size. However, his mixed record on civil rights and exploitation of conquered territories adversely affect his reputation.