Greek War of Independence: Ottoman troops began a massacre of tens of thousands of Greeks (depicted) on the island of Chios.

The Greek War of Independence, also known as the Greek Revolution or the Greek Revolution of 1821, was a successful war of independence by Greek revolutionaries against the Ottoman Empire between 1821 and 1829. In 1826, the Greeks were assisted by the British Empire, Kingdom of France, and the Russian Empire, while the Ottomans were aided by their vassals, especially by the Eyalet of Egypt. The war led to the formation of modern Greece, which would be expanded to its modern size in later years. The revolution is celebrated by Greeks around the world as independence day on 25 March.

The Ottoman Empire, also called the Turkish Empire, was an imperial realm that controlled much of Southeast Europe, West Asia, and North Africa from the 14th to early 20th centuries; it also controlled parts of southeastern Central Europe, between the early 16th and early 18th centuries.

The Chios massacre was a catastrophe that resulted in the death, enslavement, and flight of about four-fifths of the total population of Greeks on the island of Chios by Ottoman troops during the Greek War of Independence in 1822. It is estimated that up to 100,000 people were killed or enslaved during the massacre, while up to 20,000 escaped as refugees. Greeks from neighboring islands had arrived on Chios and encouraged the Chiotes to join their revolt. In response, Ottoman troops landed on the island and killed thousands. The massacre of Christians provoked international outrage across the Western world and led to increasing support for the Greek cause worldwide.

Chios is the fifth largest Greek island, situated in the northern Aegean Sea, and the tenth largest island in the Mediterranean Sea. The island is separated from Turkey by the Chios Strait. Chios is notable for its exports of mastic gum and its nickname is "the Mastic Island". Tourist attractions include its medieval villages and the 11th-century monastery of Nea Moni, a UNESCO World Heritage Site.