Hawk of May is the first installment in Gillian Bradshaw’s "Down The Long Wind" trilogy.
 Published initially in 1980 by Simon and Schuster, "Hawk of May" is a bildungsroman set in the time of King Arthur and centered on Gwalchmai ap Lot (Gawain, as he is better known).
The First English Civil War (1642–1646) began the series of three wars known as the English Civil War (or "Wars").
 "The English Civil War" was a series of armed conflicts and political machinations that took place between Parliamentarians and Royalists from 1642 until 1651, and includes the Second English Civil War (1648–1649) and the Third English Civil War (1649–1651).
Kingdom of Summer is the second book in a trilogy of fantasy novels written by Gillian Bradshaw.
 The novel tells of the ascendancy of King Arthur and the planting of the seeds of his downfall.
 The tale is recounted by Rhys ap Sion, a Dumnonian farmer who becomes the servant of Gwalchmai ap Lot (the hero of the preceding book, "Hawk of May").
Rice Powell was a Welsh Colonel in the Parliamentary army during the First English Civil War.
 In the Second English Civil War he allied himself with the Royalist cause.
 English Civil Wars.
 He fought in South Wales and played a significant part in events between 1642 and 1649 including a senior role during the Battle of St. Fagans.
In Winter's Shadow is the final book in a trilogy of fantasy novels written by Gillian Bradshaw.
 It tells the story of King Arthur's downfall, as recounted by his wife Gwynhwyfar.
Gillian Marucha Bradshaw (born May 14, 1956) is an American writer of historical fiction, historical fantasy, children's literature, science fiction, and contemporary science-based novels, who currently lives in Britain.
 Her serious historical novels are often set in classical antiquity — Ancient Egypt, Ancient Greece, the Byzantine Empire, Saka and the Greco-Bactrian Kingdom, Imperial Rome, Sub-Roman Britain and Roman Britain.
 She has also written two novels set in the English Civil War.
The Second English Civil War (1648–1649) was the second of three wars known collectively as the English Civil War (or "Wars"), which refers to the series of armed conflicts and political machinations which took place between Parliamentarians and Royalists from 1642 until 1651 and also include the First English Civil War (1642–1646) and the Third English Civil War (1649–1651).
Arthur Hailey (April 5, 1920 – November 24, 2004) was a British-Canadian novelist whose plot-driven storylines were set against the backdrops of various industries.
 His meticulously-researched books, which include such best sellers as "Hotel" (1965), "Airport" (1968), "Wheels" (1971), "The Moneychangers" (1975), and "Overload" (1979), have sold 170 million copies in 38 languages.
Robert Peebles "Bob" Arthur (born 1943) is primarily a poet, but also a novelist, a short-story writer, a playwright, a critic, a director, and a professor.
 He has written and published fourteen books of poetry and plays, two novels, and a book of short stories, and has had nineteen poem/plays, plays in verse, and musical programs featuring poetry produced.
 He is known nationally and internationally for taking poetry to the stage.
 He has written approximately 1,500 articles on the theatre for newspapers and magazines and produced numerous poetry shows, as well as poetry readings.
 A finalist for Poet Laureate of Virginia in 2008 and 2010, he remains best known for his book of poems, "Hymn to the Chesapeake," the best-selling book in the history of Road Publishers.
 Three of his works have been produced as dance suites in poetry.
 In addition, he has ghost written two novels, three biographies, and a history of music.
Giles Kristian (born 1975) is a bestselling novelist, known for his action adventure novels in the historical fiction genre.
 He is best known for his "Raven" series, about a young man’s coming of age amongst a band of Viking warriors.
 His first novel, the bestselling "Raven: Blood Eye," was published to great acclaim (including an accolade from Bernard Cornwell).
 Two further novels complete the "Raven" Saga, "Sons of Thunder" and "Odin's Wolves", and to date the books have been published in eight languages.
 He has written two books set during the English Civil War 'The Bleeding Land' and 'Brothers Fury' published by Transworld Publishers.
 In 2015 he co wrote 'Golden Lion' with Wilbur Smith, part of Smith's best selling Courtney series.
 He is currently writing the second book in the Raven prequel series, following the exploits of Sigurd 'The Lucky', the first being the 2014 release "God of Vengeance".

Question: Who has also written two novels set in the English Civil War,  Gillian Bradshaw or Arthur Hailey?
Answer: Gillian Marucha Bradshaw