Battles of Cabin Creek

June 20: Start of the Third Italian War of Independence

1866 (MDCCCLXVI) was a common year starting on Monday of the Gregorian calendar and a common year starting on Saturday of the Julian calendar, the 1866th year of the Common Era (CE) and Anno Domini (AD) designations, the 866th year of the 2nd millennium, the 66th year of the 19th century, and the 7th year of the 1860s decade. As of the start of 1866, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.

Events

January–March

January 1
- Fisk University, a historically black university, is established in Nashville, Tennessee.
- The last issue of the abolitionist magazine The Liberator is published.
January 6 – Ottoman troops clash with supporters of Maronite leader Youssef Bey Karam,^[1] at St. Doumit in Lebanon; the Ottomans are defeated.
January 12
- The Royal Aeronautical Society is formed as The Aeronautical Society of Great Britain in London, the world's oldest such society.
- British auxiliary steamer SS London (1864) sinks in a storm in the Bay of Biscay, on passage from the Thames to Australia, with the loss of 244 people, and only 19 survivors.
January 18 – Wesley College, Melbourne, is established.
January 26 – Volcanic eruption in the Santorini caldera begins.
February 7 – Battle of Abtao: A Spanish naval squadron fights a combined Peruvian-Chilean fleet, at the island of Abtao, in the Chiloé Archipelago of southern Chile.
February 13 – The first daylight bank robbery in United States history during peacetime takes place in Liberty, Missouri. This is considered to be the first robbery committed by Jesse James and his gang, although James's role is disputed.
February 26 – The Calaveras Skull is discovered in California. Purported to be evidence of humans in North America during the Pliocene epoch, it turns out to be a hoax.
March 13 – The United States Congress overwhelmingly passes the Civil Rights Act of 1866, the first federal legislation to protect the rights of African-Americans; U.S. President Andrew Johnson vetoes the bill on March 27, and Congress overrides the veto on April 9.^[2]
March 31 – A total lunar eclipse occurs.

April–June

April 4 – Alexander II of Russia narrowly escapes an assassination attempt in the city of St Petersburg.
April 8 – The kingdoms of Italy and Prussia form an alliance against the Austrian Empire.
April 10 – The American Society for the Prevention of Cruelty to Animals (ASPCA) is founded in New York City by Henry Bergh.
May 2 – Battle of Callao: Peruvian defenders fight the Spanish fleet.
May 7 – Student Ferdinand Cohen-Blind makes a failed attempt to assassinate Otto von Bismarck in Unter den Linden in Berlin.

May 10 – London bank Overend, Gurney and Company collapses, precipitating Panic of 1866.
May 16 – The United States Congress approves the minting of a nickel 5-cent coin (nickel), eliminating its predecessor, the half dime.
May 24 – Battle of Tuyutí: 32,000 soldiers of the Triple Alliance defeat 24,000 Paraguayan soldiers few miles north of the Paraná, Argentina, in the Paraguayan War, with 16,000 casualties.
May 26 – First production of the comic opera Cox and Box by F. C. Burnand and Arthur Sullivan at Moray Lodge, Kensington
May 30 – Bedrich Smetana's comic opera The Bartered Bride premiered in Prague.^[3]
June 2 – Fenian forces skirmish with Canadian militia at the battles of Ridgeway and Fort Erie.
June 5 – Calculations indicate Pluto (not known at this time) reaches its only aphelion (furthest point from the Sun) between 1618 and August 2113.
June 8 – The Parliament of Canada meets for the first time in Ottawa.
June 11 – The Agra High Court is established (later shifted to the Allahabad High Court).
June 14 – The Austro-Prussian War begins when the Austrians and most of the medium German states declare war on Prussia.
June 20 – The Kingdom of Italy declares war on Austria.
June 22 – In Sweden, the Riksdag of the Estates votes to replace itself by an elected two-chamber Riksdag.
June 27–29 – Battle of Langensalza: The Prussians defeat the Hanoverian army.

July–September

July 3 – Battle of Königgrätz: the Prussian army under King Wilhelm and Helmuth von Moltke defeats the Austrian army of Ludwig von Benedek, leading to a decisive Prussian victory in the Austro-Prussian War.
July 5 – Princess Helena, third daughter of Queen Victoria, marries Prince Christian of Schleswig-Holstein.
July 10 – Reconstruction Treaty with Choctaw & Chickasaw, completing the abolition of slavery in the United States; see also Choctaw freedmen.
July 13 (July 1 Old Style) – The first Constitution of Romania is issued.
July 20 – Naval Battle of Lissa: The Austrian fleet under Wilhelm von Tegetthoff defeats the Italian fleet of Carlo di Persano.
July 24 – Reconstruction: Tennessee becomes the first U.S. state to be readmitted to the Union following the American Civil War.
July 25 – The United States Congress passes legislation authorizing the four-star rank of General of the Army (later reestablished as a five-star rank); Lieutenant General Ulysses S. Grant becomes the first to have this rank.

July 27 – The SS Great Eastern successfully completes laying the transatlantic telegraph cable between Valentia Island, Ireland, and Heart's Content, Newfoundland, permanently restoring a communications link.
July 28 – The Metric Act of 1866 becomes law and legalizes the standardization of weights and measures in the United States.
August 23 – The Treaty of Prague ends the Austro-Prussian War. The Duchy of Limburg leaves the German Confederation.
September – The Great Tea Race of 1866 ends in London, narrowly won by the clipper ship Taeping.
September 22 – Paraguay successfully defends Curupayty against the Triple Alliance in the Paraguayan War, killing more than 5,000 while sustaining just about 50 casualties.

October–December

October 12 – The Treaty of Vienna ends the war between Austria and Italy; it formalizes the annexation of Venetia by Italy.
October 14 – French troops under the command of Rear Admiral Pierre-Gustave Roze land at Ganghwa Island, Korea, as part of a punitive expedition against that kingdom for the execution of French Jesuit priests. It is the first military contact between Korea and a Western force.
October 22 – The office of State President of the South African Republic is created by constitutional amendment approved at a session of the Volksraad.^[4]
November 7 – The Ruse–Varna railway line (the first railway in Bulgaria) officially opens.
December 12– Oaks explosion: The worst mining disaster in England kills 383 miners and rescuers.
December 18 – The College of Wooster is founded in Ohio.^[5]

Date unknown

Federalist revolts occur in Argentina.
Alfred Nobel invents dynamite in Germany.
Foundation of the predecessors of Nestlé S.A., the Anglo-Swiss Milk Company and Farine Lactée Henri Nestlé.
The Minneapolis Milling Company, predecessor of General Mills, builds its own mills.
Marcus Jastrow arrives in the United States to become rabbi of Congregation Rodeph Shalom in Philadelphia.
The recommendations of the state Girls' School Committee of 1866 result in a series of progressive reforms in women's rights in Sweden.
The Famine of 1866–68 begins in Finland.
Erasmus Jacobs discovers the 21.25-carat (4.250 g) Eureka Diamond near Hopetown on the banks of the Orange River in the Cape of Good Hope.
Magirus Kommamditist, as predecessor of a major worldwide commercial vehicles manufacturing brand, Iveco, is founded in Baden-Württemberg, Germany.^{[citation needed]}