Template:On this day - May 1

Ramón y Cajal

• 1243 – Alfonso X of Castile, while still an Infante, reconquers the city of Murcia (present-day Spain) from the Muslims.
• 1285 – The Muslim troops of Ayyad Al-Asseni attack the Castle of Sanlúcar de Barrameda (present-day Spain), massacring a large number of Christian settlers, but without managing to take it.
• 1287 – In Sicily, the forces of Roger of Lauria (of the Crown of Aragon) take the Town and Castle of Augusta, which had been held by the Kingdom of Naples.
• 1751 – Birth of José Felipe Flores, protomedicus of the Captaincy General of Guatemala and physician to the King of Spain (d. 1814).
• 1852 – Birth of Santiago Ramón y Cajal, Spanish physician specializing in histology and anatomical pathology, awarded the Nobel Prize in Medicine in 1906 (d. 1934).
• 1853 – Argentina enacts its first and only national constitution, amended on seven occasions.
• 1855 – The Holy See breaks off diplomatic relations with the Government of Spain after the enactment of the Madoz Confiscation Law.
• 1890 – In Barcelona (Spain), anarchist-leaning workers' societies call a general strike to win the eight-hour day, while in Elche the first May Day demonstration takes place.
• 1898 – During the first battle of the Spanish–American War, the United States fleet destroys the Spanish fleet in the Pacific Ocean.
• 1904 – Death of Augusto González de Linares, Spanish geologist and zoologist (b. 1845).
• 1909 – In Buenos Aires (Argentina), police under the command of Ramón L. Falcón shoot dead 14 striking workers and wound another 80.
• 1953 – In Buenos Aires (Argentina), several hundred thousand workers attend, despite bomb threats, the Workers' Day speech of constitutional president Juan Domingo Perón. Seven bombs explode, without casualties.
• 1954 – In Honduras, the workers of the United States companies United Fruit Co. and Standard Fruit Co. begin the largest strike in that country's history.
• 1972 – In Nicaragua, president General Anastasio Somoza Debayle hands power to the triumvirate of the National Governing Junta, made up of Doctor Alfonso Lovo Cordero, General Roberto Martínez Lacayo (Liberals) and Doctor Fernando Agüero Rocha (Conservative), so as to be re-elected in 1974.
• 1982 – Hostilities in the Falklands War begin with the first air combats.
• 2006 – The Great American Boycott takes place, with millions of Latino immigrants going on strike and joining in a labor boycott both in that country and throughout Latin America.
• 2006 – The government of Puerto Rico goes bankrupt, forcing the closure of schools and other agencies.
• 2014 – Death of Juan Formell, Cuban musician, bassist, composer and arranger, bandleader of Los Van Van (b. 1942).
• 2021 – Death of Rafael Roncagliolo, Peruvian sociologist, politician and journalist (b. 1944).