On this day: 28 March

Roman emperor Caligula accepts the titles of the Principate, bestowed on him by the Senate.

Roman Emperor Valentinian I appoints his brother Flavius Valens co-emperor.

The Great German Pilgrimage, which had been under attack by Bedouin bandits for three days, is rescued by the Fatimid governor of Ramla.

The foundation stone of Valletta, Malta's capital city, is laid by Jean Parisot de Valette, Grand Master of the Sovereign Military Order of Malta.

Irish Confederate Wars: Donough MacCarty, 1st Earl of Clancarty, signed the First Ormond Peace for the Confederates in exchange for greater freedom of religion.

War of the Austrian Succession: In the Battle of Vilshofen, Austrian forces defeat French forces.

Juan Bautista de Anza finds the site for the Presidio of San Francisco.

Partitions of Poland: The Duchy of Courland and Semigallia, a northern fief of the Polish–Lithuanian Commonwealth, ceases to exist and becomes part of Imperial Russia.

Treaty of Florence is signed, ending the war between the French Republic and the Kingdom of Naples.

German astronomer Heinrich Wilhelm Matthias Olbers discovered Pallas, the second asteroid to be identified, but at the time considered to be a planet.

Peninsular War: France defeats Spain in the Battle of Medellín.

War of 1812: In the Battle of Valparaíso, two American naval vessels are captured by two Royal Navy vessels.

First concert of the Vienna Philharmonic Orchestra, conducted by Otto Nicolai.

First Taranaki War: The Battle of Waireka begins.

American Civil War: In the Battle of Glorieta Pass, Union forces stop the Confederate invasion of the New Mexico Territory. The battle began on March 26.

The Hexham Abbey high-altar cross, amongst the most important works produced that year by the Keswick School of Industrial Art, was unveiled on Good Friday.

Henri Fabre becomes the first person to fly a seaplane, the Fabre Hydravion, after taking off from water runway Étang le Barre, near Marseille.

General John J. Pershing, during World War I, cancels 42nd 'Rainbow' Division's orders to Rolampont for further training and diverted it to the occupy the Baccarat sector. Rainbow Division becomes "the first American division to take over an entire sector on its own, which it held longer than any other American division-occupied sector alone for a period of three months".

Palm Sunday tornado outbreak of 1920 affects the Great Lakes region and Deep South states.

Spanish Civil War: Generalissimo Francisco Franco conquers Madrid after a three-year siege.

The US Department of State released the Acheson–Lilienthal Report, a proposal for the international control of nuclear weapons.

The State Council of the People's Republic of China dissolves the government of Tibet.

Civil rights movement: Over one hundred high school students conducted a sit-in protest in Rome, Georgia.

The US Supreme Court hands down 5–3 decision in Stump v. Sparkman, a controversial case involving involuntary sterilization and judicial immunity.

A coolant leak at the Three Mile Island's Unit 2 nuclear reactor outside Harrisburg, Pennsylvania leads to the core overheating and a partial meltdown.

United States President George H. W. Bush posthumously awards Jesse Owens the Congressional Gold Medal.

Athens International Airport Eleftherios Venizelos begins operation.

At least one million union members, students and unemployed take to the streets in France in protest at the government's proposed First Employment Contract law.

The region of Uusimaa (with the capital city Helsinki) is temporarily isolated from the rest of Finland due to increased COVID-19 infections.