In hoc signo vinces
In hoc signo vinces (Latin pronunciation: [ɪn hoːk ˈsɪŋnoː ˈwɪnkeːs]) is a Latin rendering of the Greek phrase "ἐν τούτῳ νίκα" en touto nika, (Ancient Greek: [en tǒːtɔːi̯ níkaː]) and means "in this sign you will conquer".
According to legend, Constantine I adopted this Greek phrase, "ἐν τούτῳ νίκα" (in this, win) as a motto after his vision of a chi rho in the sky just before the Battle of Milvian Bridge against Maxentius on 28 October 312. The early Christian symbol consists of a monogram composed of the Greek letters chi (X) and rho (P), the first two letters in the name Christ (Greek: Χριστός). In later periods, the christogram "IHS" both stood for the first three letters of "Jesus" in majuscule Greek lettering (ΙΗΣΟΥΣ) and "in hoc signo" from the legend.
The historian Eusebius states that Constantine was marching with his army (Eusebius does not specify the actual location of the event, but it is clearly not in the camp at Rome), when he looked up to the sun and saw a cross of light above it, and with it the Greek words "ἐν τούτῳ νίκα" ("In this, conquer"), often rendered in Latin as In hoc signo vinces "in this sign, you will conquer"). At first, Constantine did not know the meaning of the apparition, but on the following night, he had a dream in which Christ explained to him that he should use the sign of the cross against his enemies. Eusebius then continues to describe the Labarum, the military standard used by Constantine in his later wars against Licinius, showing the Chi-Rho sign.
The phrase appears prominently placed as a motto on a ribbon unfurled with a passion cross to its left, beneath a window over the Scala Regia, adjacent to the equestrian statue of Emperor Constantine, in the Vatican. Emperors and other monarchs, having paid respects to the Pope, descended the Scala Regia, and would observe the light shining down through the window, with the motto, reminiscent of Constantine's vision, and be reminded to follow the Cross. They would thence turn right into the atrium of St. Peter's Basilica, ostensibly so inspired.
Use by nobility 
It appears on the coat of arms borne by Jan III Sobieski and other members of the Sobieski line; it is also on the coat of arms of the Irish noble dynasty of O'Donnell of Tyrconnell, the Noble House of Vassallo, and is the motto of the Sacred Military Constantinian Order of Saint George.
It was used as a motto by the Portuguese monarchy. According to the legend, King Afonso I de Portugal saw the sign of the "quinas" -Portugal's heraldic symbol- at the battle of Ourique, adopting them as the national symbol and the motto as a consequence. This legend is told in The Lusiads by Luís de Camões.
Other uses 
The phrase also appears on the "coat of arms" of Pall Mall cigarettes, together with "per aspera ad astra," a Latin phrase meaning "To the stars through difficulties" or "Through hardships to the stars."
Cultural references 
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- Appears on the Knight Templar Cross in the York Rite branch of Freemasonry.
- Public motto of the Sigma Chi Fraternity.
- Motto of the Royal Black Institution.
- Motto of the Sisters of Charity of Montreal, The "Grey Nuns of Montreal".
- Motto of the English Defence League (EDL)
- Motto of the Norwegian Defence League
- Motto of the Felony Investigative Assistance Team (FIAT SWAT) Police Taskforce (Illinois, USA)
- Inscribed in Greek on the flag of the Sacred Band of the Greek War of Independence.
- Inscribed in Greek on the coat of arms and flag of the 22nd Tank Brigade (XXII ΤΘΤ) of the Greek Army.
- Inscribed on the banner of the Sanfedismo in 1799
- Motto of the Royal Army Chaplains Department
- In Hoc Signo Vinces appears prominently on four of the six regimental colors of the Irish Brigade that served in the armies of France from 1690 to 1792.
- Former motto of the Canadian Forces Chaplains Branch, which was replaced in 2006.
- Appears on the patches of Marine All-Weather Fighter-Attack Squadron 533.
- Seen on the coat of arms of the second mechanized infantry battalion, Norwegian Army.
- Motto of C Company, 1st Battalion, The Princess of Wales's Royal Regiment (British Army)
- Used by the Lebanese Forces, a Lebanese Christian resistance.
- Motto of 814th Squadron of the British Fleet Air Arm.
- Motto of 7th Scout Ranger Company, Philippine Army
- Motto of 2nd battalion of the Norwegian army
- Motto of the 54th Massachusetts, (African-American Regiment) On their regiment flag showing a gold Cross and star, Civil War
- The motto was used on the regimental flags of certain foreign regiments of the French Army of the 18th Century, most notably the "Wild Geese" Irish regiments (such as Rooth's, Lally's, Berwick's, Dillon's, Bulkeley's and Clare's) and Swiss Regiments.
- Motto of 4th brigade Spiders of the Croatian army
- Motto of 3 Troop, AWG, United States Army.
- Motto of 2050 (Leyland) Squadron, Air Training Corps (UK)
- Motto of the US Navy destroyer, USS Waldron (DD-699)
- Motto of the Finnish defense forces reconnaissance
- Motto of Sigma Chi Fraternity.
- Motto of Holy Cross College, Kalutara, Sri Lanka
- Motto of the College of the Holy Cross in Worcester, Massachusetts, USA.
- Motto of Madras Christian College High School, Chetput, Chennai, India.
- Motto of the Wah Yan College, Hong Kong and Wah Yan College, Kowloon, two Jesuit-run secondary schools in Hong Kong.
- Appears on the crest of Madras Christian College of Chennai, India.
- Appears on the crest of the Royal and Prior Comprehensive School, Raphoe, Co. Donegal, Ireland
- Appears on the Donegal Coat of Arms, Donegal, Ireland.
- Motto of Iona College in Brisbane, Australia.
- Appears on the crest of St. Eunan's College of Letterkenny, County Donegal, Ireland
- Motto of Waverley Christian College, Victoria, Australia
- Motto of Marist Brothers High School (Fiji)
- Motto of Colegio Nacional de Concepción del Uruguay (Argentina)
- Motto of Sacred Heart R.C. Secondary School, London, England
- Motto of Pope John Paul II High School, Hendersonville, Tennessee
- Adapted Motto of Holy Name High School (Reading, Pennsylvania)
- motto of Holyrood R.C. Secondary School, Glasgow, Scotland
- Motto of Santa Clara High School, Oxnard, California, USA
- Motto of Quitman High School, Quitman, Louisiana USA
- Motto of Coal Hill Road Secondary School, Brisbane, Australia
- Motto of Instituto Tecnológico de Mérida, Mérida, Mexico
- Motto of St Michael's, Christchurch, Primary and secondary, New Zealand
- Motto of St Peter Chanel School, Motueka, New Zealand
- Motto of Holy Cross College, Arima, Trinidad
- Motto of Hood Theological Seminary, Salisbury, North Carolina
- Motto of Holy Cross School, Winnipeg, Manitoba, Canada.
- Motto of Georgian Institute of Public Affairs, Tbilisi, Georgia
- Motto of Bishop Simon Bruté College Seminary, Indianapolis, Indiana
- Motto of Liverpool College, Bahía Blanca, Argentina
- Motto of St. Josephs Convent Grammar School, Donaghmore, County Tyrone, Northern Ireland
- Motto of Holy Cross High School, Surrey, British Columbia, Canada.
- Motto of The Estancia High School Football Team, in Costa Mesa, California.
- Latin phrase on the Logo of TEAM C.A.P.A. (Cavite Alabang Paranaque Airsofters) An active airsoft team in the Philippines.
- Crest of the Royal Hockey Club, Antwerp, Belgium
- Motto of Birkirkara, Malta.
- Motto of the Norwegian soccer-team Storkanonan.
- Motto of the Ipswich Brothers Rugby League club, Qld Australia
- Motto of Worthing Chippingdale Cricket Club, England
- Motto of Pirita Jalgpalliklubi Reliikvia soccer team, Estonia
- Motto of the Lee Flames Rugby Team in Cleveland, Tennessee
- Motto of Kloof High School, South Africa
- Motto of Ponsonby Rugby Football Club, Auckland, New Zealand
- Motto of 2011 Holy Cross High School, Delran, NJ Varsity Soccer Team
- George Lincoln Rockwell, the founder of the American Nazi Party, wrote a political manifesto called In hoc signo vinces in 1960.
- Appears on the crest of the O'Donnell clan.
- Is the motto on the coat of arms of the city of Plzeň and is used by Pilsner Urquell
- Is the motto on the crest of the English Defence League.
- Is the motto found on any pack of Pall Mall brand cigarettes.
- Is written under the statue in front of the bank in the game Postal 2.
- Is the sign of the Templar organization Abstergo in the game Assassin's Creed II.
- Is a recurring phrase in the HBO series Carnivàle.
- Is the motto on the crest of the House of Di Santis.
- Appears in Thomas Pynchon's Gravity's Rainbow
- Appears at the top of a wall in a 1974 piece of artwork by Zdzisław Beksiński
- Chadwick, Owen. 1981. The Popes and European Revolution. Oxford University Press. ISBN 0-19-826919-6. p. 474.
- "Story of Coat of Arms". 24 November 2010. Retrieved 4 January 2012.