Question: Who plays the legendary figure featured in Historia Regum Britanniae in the show Once Upon a Time?

Context paragraphs:
paragraph_text: Cherin was a legendary king of the Britons as recounted in Geoffrey of Monmouth's "Historia Regum Britanniae". His father was King Porrex II and he was succeeded by his three sons in turn, Fulgenius, Edadus, and Andragius.
title: Cherin
paragraph_text: In 2013, the league expanded with the addition of two new franchises to play in 2014, the Los Angeles Kiss (owned by Gene Simmons and Paul Stanley of the legendary rock band Kiss) and the Portland Thunder.
title: Arena Football League
paragraph_text: Chivalry and the ethos of courtly love developed in royal and noble courts. This culture was expressed in the vernacular languages rather than Latin, and comprised poems, stories, legends, and popular songs spread by troubadours, or wandering minstrels. Often the stories were written down in the chansons de geste, or "songs of great deeds", such as The Song of Roland or The Song of Hildebrand. Secular and religious histories were also produced. Geoffrey of Monmouth (d. c. 1155) composed his Historia Regum Britanniae, a collection of stories and legends about Arthur. Other works were more clearly history, such as Otto von Freising's (d. 1158) Gesta Friderici Imperatoris detailing the deeds of Emperor Frederick Barbarossa, or William of Malmesbury's (d. c. 1143) Gesta Regum on the kings of England.
title: Middle Ages
paragraph_text: When a Stranger Calls is a 2006 American horror film directed by Simon West and written by Jake Wade Wall. The film stars Camilla Belle, Brian Geraghty, Katie Cassidy, and Clark Gregg. Belle plays a babysitter who starts to receive threatening phone calls from an unidentified stranger, played by both Tommy Flanagan and Lance Henriksen. The film is a remake of Fred Walton's 1979 horror film of the same name which became a cult classic for its legendary opening 20 minutes, which this remake extends to a feature-length film.
title: When a Stranger Calls (2006 film)
paragraph_text: Hooray for Bix! is an album by American jazz guitarist Marty Grosz and his Honorus Causa Jazz Band featuring compositions associated with legendary cornetist Bix Beiderbecke recorded in 1957 for the Riverside label.
title: Hooray for Bix!
paragraph_text: Metaris Valley () is a small, rounded cirque valley with steep sides and residual névé, lying west of Derrick Peak in the Britannia Range in Antarctica. It was named in association with Britannia by a University of Waikato geological party, 1978–79, led by Michael Selby. "Metaris" is the historical name of a bay in Roman Britain, known today as The Wash.
title: Metaris Valley
paragraph_text: Beverley Elliott (born 31 December) is a Canadian actress and singer - songwriter. She is best known for playing the role of Granny in Once Upon a Time, Maggie Krell in Harper's Island, Brick Bannerman in Kingdom Hospital and Sally Duffield in Bordertown.
title: Beverley Elliott
paragraph_text: Catellus () was a legendary king of the Britons, as recounted in Geoffrey of Monmouth's work "Historia Regum Britanniae". According to Geoffrey, he was the son of King Gerennus and was succeeded by his son, Millus. In some versions of the "Brut y Brenhinedd", a series of Welsh versions of Geoffrey's "Historia", Catellus is succeeded by his son Coel, who is then succeeded by his own son Porrex II.
title: Catellus
paragraph_text: Lindum Valley is an ice-filled valley that opens northward to Hatherton Glacier, lying west-northwest of Derrick Peak in the Britannia Range, Antarctica. It was named in association with Britannia by a University of Waikato geological party, 1978–79, led by Michael Selby, "Lindum" being an old Roman placename for present-day Lincoln, England.
title: Lindum Valley
paragraph_text: Aída Bortnik (7 January 1938 – 27 April 2013) was an Argentine screenwriter, nominated for an Academy Award for her work in the film "La historia oficial" (1985). She has the notable distinction of having written the screenplay for both the first Argentine film nominated for an Academy Award ("The Truce", 1974) and the first Argentine film to win an Academy Award ("La historia oficial").
title: Aída Bortnik
paragraph_text: However, from 1971 to 1975, NBA teams played preseason exhibitions against American Basketball Association teams. In the early days of the NBA, league clubs sometimes challenged the legendary barnstorming Harlem Globetrotters, with mixed success. The NBA has played preseason games in Europe and Asia. In the 2006 and 2007 seasons, the NBA and the primary European club competition, the Euroleague, conducted a preseason tournament featuring two NBA teams and the finalists from that year's Euroleague.[citation needed] In the 1998-99 and 2011-12 seasons, teams were limited to only two preseason games due to lockouts.
title: Exhibition game
paragraph_text: Peredurus () is a legendary king of the Britons in Geoffrey of Monmouth's pseudohistorical chronicle "Historia Regum Britanniae". According to Geoffrey, he was the youngest son of King Morvidus and brother of Gorbonianus, Archgallo, Elidurus, and Ingenius.
title: Peredurus
paragraph_text: The historical basis for the King Arthur legend has long been debated by scholars. One school of thought, citing entries in the Historia Brittonum (History of the Britons) and Annales Cambriae (Welsh Annals), sees Arthur as a genuine historical figure, a Romano - British leader who fought against the invading Anglo - Saxons some time in the late 5th to early 6th century. The Historia Brittonum, a 9th - century Latin historical compilation attributed in some late manuscripts to a Welsh cleric called Nennius, contains the first datable mention of King Arthur, listing twelve battles that Arthur fought. These culminate in the Battle of Badon, where he is said to have single - handedly killed 960 men. Recent studies, however, question the reliability of the Historia Brittonum.
title: King Arthur
paragraph_text: Porrex II was a legendary king of the Britons as recounted in Geoffrey of Monmouth's "Historia Regum Britanniae". His father was King Millus and he was succeeded by his son, Cherin.
title: Porrex II
paragraph_text: The Wielkopolska Chronicle (or "Chronicle of Greater Poland", ) is an anonymous medieval chronicle describing supposed history of Poland from legendary times up to the year 1273. It was written in Latin at the end of the 13th or the beginning of the 14th century.
title: Wielkopolska Chronicle
paragraph_text: After the Anglo - Saxon period, Britain was used as a historical term only. Geoffrey of Monmouth in his pseudohistorical Historia Regum Britanniae (c. 1136) refers to the island as Britannia major (``Greater Britain ''), to distinguish it from Britannia minor (`` Lesser Britain''), the continental region which approximates to modern Brittany, which had been settled in the fifth and sixth centuries by migrants from Britain. The term Great Britain was first used officially in 1474, in the instrument drawing up the proposal for a marriage between Cecily the daughter of Edward IV of England, and James the son of James III of Scotland, which described it as ``this Nobill Isle, callit Gret Britanee ''. It was used again in 1604, when King James VI and I styled himself`` King of Great Brittaine, France and Ireland''.
title: Great Britain
paragraph_text: Jang Chul-Woo (; born 5 April 1971) is a South Korean retired footballer who played as a midfielder. He is considered one of the legendary players in Daejeon Citizen.
title: Jang Chul-woo
paragraph_text: "Britannia Hospital" is the final part of Anderson's trilogy of films, written by David Sherwin, that follow the adventures of Mick Travis (portrayed by Malcolm McDowell) as he travels through a strange and sometimes surreal Britain. From his days at boarding school in "if..." (1968) to his journey from coffee salesman to film star in "O Lucky Man!" (1973), Travis's adventures finally come to an end in "Britannia Hospital", which sees Mick as a muckraking reporter investigating the bizarre activities of Professor Millar, played by Graham Crowden, whom he had had a run-in with in "O Lucky Man". All three films have characters in common. Some of the characters from "if..." that did not turn up in "O Lucky Man" return for "Britannia Hospital".
title: Britannia Hospital
paragraph_text: Liam Thomas Garrigan (born 17 October 1981) is an English theatre and television actor. As a youth he attended classes at Kingston upon Hull's Northern Stage Company and was a student at Wyke College, Kingston upon Hull. His first television role was as Nic Yorke in the BBC continuing drama series Holby City. He is best known for his roles as Ian Al - Harazi on the Fox series 24: Live Another Day and King Arthur in the ABC series Once Upon a Time and Transformers: The Last Knight.
title: Liam Garrigan
paragraph_text: Natoker Moto - Like a Play (2015) is a Bengali film directed by Debesh Chattopadhyay based on the Life and Struggle of a Legendary Actress of Calcutta which still impress the Theatre Movement of India.
title: Natoker Moto

Reasoning steps:
What legendary figure was featured in the Historia Regum Britanniae? >>>> Arthur
who plays Arthur in once upon a time >>>> Liam Thomas Garrigan

Answer: spans: Liam Thomas Garrigan