Template:On this day - October 17

Santiago Ramón y Cajal

• 456 – Near Piacenza (present-day Italy), the soldiers of Emperor Avitus are defeated by those of the Roman-Iberian military leader Ricimer, who becomes de facto leader of the Western Roman Empire.
• 1500 – Birth of Alonso de Orozco, Spanish religious and writer (d. 1591).
• 1533 – The Royal Cédula ordering the construction of roads in New Spain is issued in Madrid, enabling the military engineer Juan Bautista Antonelli to lay out the first Camino Real from Mexico City to the Port of Veracruz, through the Hispanic settlements of Puebla, Nueva Córdoba and Orizaba.
• 1612 – Death of Juan Felipe Mey, Spanish Hellenist, humanist, translator, writer and printer (b. 1542).
• 1810 – In Yucatán (present-day Mexico), the pro-independence forces take the city of Valladolid.
• 1813 – At El Roble (Chile), a royalist column surprises and scatters the pro-independence rebels.
• 1842 – In Peru, the Battle of Agua Santa takes place, in which the forces of Juan Francisco de Vidal defeat those of General Juan Crisóstomo Torrico, amid the military anarchy that broke out after the death of President Agustín Gamarra.
• 1910 – In Cuba, the fifth and last day of the Five Days' Hurricane is recorded; it kills some 700 people and breaks the Havana Malecón.
• 1919 – King Alfonso XIII of Spain inaugurates the Madrid Metro.
• 1920 – Birth of Miguel Delibes, Spanish professor, journalist, novelist and playwright (d. 2010).
• 1933 – Death of Fulgencio R. Moreno, Paraguayan journalist, economist, diplomat and historian (b. 1872).
• 1934 – Death of Santiago Ramón y Cajal, Spanish physician and scientist, often cited as the father of neuroscience, winner of the Nobel Prize in Medicine in 1906 (b. 1852).
• 1945 – In the Plaza de Mayo of Buenos Aires (Argentina), a massive popular gathering with military and police support mobilizes to demand the release of the Minister of Labor, Juan Domingo Perón, detained by military forces, launching the Peronist movement.
• 1963 – In Plaza Once in Buenos Aires (Argentina), the Justicialist Party (Peronist and banned by the dictatorship) holds an open council in which it declares a state of popular mobilization.
• 2003 – Because of the Bolivian conflict over the export of natural gas, President Gonzalo Sánchez de Lozada resigns from office and leaves the country.
• 2021 – Death of Robin Wood, Paraguayan comic book writer, author and film and television screenwriter (b. 1944).