2,425 articles
Okita Sōji (沖田総司)
Okita Sōji (沖田総司) was a Japanese samurai who captained the first unit of the Shinsengumi in Kyoto, fought at the Ikedaya Incident of 1864, and died of tuberculosis in 1868.
Oleg Gordievsky (Олег Антонович Гордиевский)
Oleg Gordievsky (Олег Антонович Гордиевский), KGB colonel and MI6 double agent codenamed SUNBEAM, rezident in London 1985; exposed Operation RYAN, fled in a car trunk to Finland, died 2025.
Oleg Kalugin (Олег Данилович Калугин)
Oleg Danilovich Kalugin (Олег Данилович Калугин), born 1934, former KGB major general, head of external counterintelligence 1973-1980, denounced the KGB in 1990, moved to the US in 1995, convicted of treason in absentia in 2002.
Oleg Penkovsky (Олег Владимирович Пеньковский)
Oleg Vladimirovich Penkovsky, GRU colonel who volunteered to the CIA and British intelligence in 1960, supplied Soviet missile intelligence until his KGB arrest on 22 October 1962, trial in May 1963, and execution on 16 May 1963.
Oleh Ivashchenko (Олег Іванович Іващенко) (Ukrainian general)
Oleh Ivashchenko, also Oleh Ivanovych Ivashchenko, is a Ukrainian Lieutenant General who has led the Defence Intelligence of Ukraine (HUR) since January 2026, after heading the Foreign Intelligence Service from 2024 to 2026.
Oleksandr Hrekov
Oleksandr Hrekov (Олександр Греків, also rendered Grekov; 1875 to 1959) was a Ukrainian general, Minister of Military Affairs of the Ukrainian People's Republic, and commander in the Chortkiv offensive of 1919.
Oleksandr Osetskyi
Oleksandr Osetskyi (Олександр Осецький, 1873–1936) was a Ukrainian general, a former Russian major general who served as acting commander-in-chief of the Ukrainian People's Republic army and later emigrated to Paris.
Oleksandr Syrskyi (Олександр Станіславович Сирський)
Oleksandr Syrskyi (Олександр Сирський), also known as Alexander Syrsky, is a Ukrainian colonel general who served as Commander-in-Chief of the Armed Forces of Ukraine from 2024 until his dismissal in 2026.
Oliver Hazard Perry
Oliver Hazard Perry (1785–1819) was a U.S. Navy officer who won the Battle of Lake Erie on September 10, 1813, receiving the first surrender of an entire Royal Navy squadron; famed for "We have met the enemy and they are ours."
Oliver North
Oliver North (born 1943), retired Marine lieutenant colonel and National Security Council staffer, central figure of the Iran-contra affair; convicted 1989, convictions vacated 1990-91; later Fox News host and 66th NRA president.
Oliver P. Smith
Oliver P. Smith (Oliver Prince Smith, 1893–1977), USMC general nicknamed "the Professor," commanded the 1st Marine Division at Inchon and the Chosin Reservoir breakout in Korea; not Gen. Eric M. Smith.
Oliver Sipple
Oliver "Billy" Sipple, Detroit-born Marine veteran of Vietnam, deflected Sara Jane Moore's .38 revolver as she shot at President Gerald Ford outside San Francisco's St. Francis Hotel on September 22, 1975; his subsequent outing and failed privacy suit became a landmark First Amendment case.
Olufemi Oluyede
Olufemi Olatubosun Oluyede (born 1968) is a Nigerian Army general, Chief of Defence Staff since 30 October 2025, formerly 24th Chief of Army Staff, infantry officer of the 39th Regular Course.
Olusegun Obasanjo
Olusegun Obasanjo, born in 1937 in Abeokuta, Nigeria, is a retired army general who served as military Head of State (1976–1979) and as elected President (1999–2007).
Omar al-Bayoumi (عمر البيومي)
Omar al-Bayoumi (عمر البيومي), Saudi civil aviation employee and purported student in San Diego, assisted 9/11 hijackers al-Hazmi and al-Mihdhar after their February 2000 arrival; FBI and 9/11 Commission found no knowing aid, while later declassified evidence and the families' lawsuit keep Saudi-intelligence allegations alive.
Omar al-Mukhtar (عمر المختار)
Omar al-Mukhtar (عمر المختار), a Libyan teacher and Senussi sheikh, led the armed resistance to the Italian occupation of Cyrenaica for twenty years until his capture and hanging in 1931.
Omar Bradley
Omar Nelson Bradley (1893–1981), the "GI General," commanded II Corps, First Army, and the 12th Army Group in Europe, served as Chairman of the Joint Chiefs of Staff, and became General of the Army in 1950.
Omar García Harfuch
Omar García Harfuch, Mexico's Secretary of Security and Citizen Protection under Claudia Sheinbaum since 2024 and former Mexico City police chief (2019-2023), survived a 2020 CJNG assassination attempt and leads the National Security Strategy.
Omar Pasha
Omar Pasha, also Omer Pasha (Ömer Lütfi Paşa), born Mihajlo Latas, was an Ottoman field marshal of Serb origin who led Ottoman armies in the Crimean War.
Omer Ahmed Bokhari
Omer Ahmed Bokhari, also known as Syed Omer Ahmed Bokhari, is a three-star general of the Pakistan Army serving as Corps Commander Peshawar since May 2024.
Omer Tischler (עומר טישלר)
Omer Tischler (עומר טישלר), born 1975 in Karmiel, is an Israeli Air Force major general who became the 20th IAF commander on May 5, 2026, after serving as IAF chief of staff and deputy commander during the Gaza and Iran wars.
Onna-musha (女武者)
Onna-musha (女武者), also called onna-bugeisha (女武芸者), were female warriors of Japan's bushi (samurai) class, trained mainly with the naginata to defend home and castle; famous figures include Tomoe Gozen and Nakano Takeko.
Orde Wingate
Orde Charles Wingate (1903–1944), British major general and DSO with two bars, founded the Special Night Squads in Palestine, led Gideon Force in Ethiopia, and commanded the Chindits in Burma, dying in a B-25 crash on 24 March 1944.
Order of Assassins
Order of Assassins: European name for the Nizari Ismailis, whose Alamut state (1090-1256) was founded by Hasan-i Sabbah; Marco Polo's hashish-and-garden legends are largely fabricated.
Oruç Reis
Oruç Reis, also known as Baba Oruç and first bearer of the name Barbarossa, was an Ottoman corsair who seized Algiers from Spanish control in 1516.
Osama bin Laden
Osama bin Laden (Usama bin Ladin, 1957–2011), Saudi-born founder of al Qaeda, directed the 1998 embassy bombings, USS Cole attack, and 9/11; killed by U.S. Navy SEALs in Abbottabad, Pakistan, May 2, 2011.
Osami Nagano (永野修身)
Osami Nagano (永野修身, 1880–1947) was a Fleet Admiral and Chief of the Imperial Japanese Navy General Staff, 1941–1944, who approved the Pearl Harbor attack, was tried as a Class A war criminal, and died during the Tokyo trial before verdict.
Oscar Jenkins
Oscar Jenkins, Australian teacher from Melbourne who joined Ukraine's International Legion in 2024, was captured by Russia in December 2024 and sentenced to 13 years as a mercenary by a Luhansk court; reports of his execution were disproven.
Osceola
Osceola (Asi-Yaholo, c. 1804–1838), born Billy Powell, was a Creek-born Seminole warrior, not a chief, who led resistance to Indian removal in the Second Seminole War, defeated U.S. forces at Withlacoochee, and died a prisoner at Fort Moultrie after capture under a flag of truce.
Ōshima Yoshimasa
Ōshima Yoshimasa (大島義昌) was a Japanese army general from Chōshū who fought in the Boshin, Sino-Japanese, and Russo-Japanese Wars and served as the first Kwantung Governor from 1906 to 1912.