Question: Who were the parents of the King with a mistress named Rosamund Clifford?
Context: Fair Rosamond is an English historical opera in four acts composed by John Barnett, written in 1837 to a libretto by Charles Zachary Barnett, after the legend of Rosamund Clifford ("Fair Rosamond" or the "Rose of the World"), the 12th century mistress of King Henry II who was said to have been poisoned by the King's wife, Queen Eleanor.  In his opera, Barnett effects a happier ending. Ricardo Caicedo is a well-to-do businessman in Bogotá, who in all appearances has a happy family life.  His wife, Elena is devoted to him and the couple have a young son.  However, Ricardo has been having an affair with a mistress named Manuela, which started a year ago.  One day, in order to be with his mistress, Ricardo pretends to have a business meeting with several Argentinian associates at the Nogal Club.  His lie is about to be uncovered when a terrorist placed a bomb at the club where Ricardo was supposed to be.  His wife is worried about his safety and calls him.  Ricardo is on the other side of town leaving Manuela’s house.  To avoid revealing his infidelity Ricardo is determined to prove that he was at the scene of the attack.  Aided by his friend Guzman, Ricardo invents an elaborate lie which portrays him as being one of the many victims of the terrorist attack.  He is mistaken to be the saviour of a little girl's life and he becomes a hero. Henry II (5 March 1133 – 6 July 1189), also known as Henry Curtmantle (French: "Court-manteau" ), Henry FitzEmpress or Henry Plantagenet, ruled as Count of Anjou, Count of Maine, Duke of Normandy, Duke of Aquitaine, Count of Nantes, King of England and Lord of Ireland; at various times, he also controlled Wales, Scotland and Brittany.  Henry was the son of Geoffrey of Anjou and Matilda, daughter of Henry I of England.  He became actively involved by the age of 14 in his mother's efforts to claim the throne of England, then occupied by Stephen of Blois, and was made Duke of Normandy at 17.  He inherited Anjou in 1151 and shortly afterwards married Eleanor of Aquitaine, whose marriage to Louis VII of France had recently been annulled.  Stephen agreed to a peace treaty after Henry's military expedition to England in 1153, and Henry inherited the kingdom on Stephen's death a year later. William Kingdon Clifford FRS (4 May 1845 – 3 March 1879) was an English mathematician and philosopher.  Building on the work of Hermann Grassmann, he introduced what is now termed geometric algebra, a special case of the Clifford algebra named in his honour.  The operations of geometric algebra have the effect of mirroring, rotating, translating, and mapping the geometric objects that are being modelled to new positions.  Clifford algebras in general and geometric algebra in particular have been of ever increasing importance to mathematical physics, geometry, and computing.  Clifford was the first to suggest that gravitation might be a manifestation of an underlying geometry.  In his philosophical writings he coined the expression "mind-stuff". John Clifford, 9th Baron Clifford, (8 April 1435 – 28 March 1461), was a Lancastrian military leader during the Wars of the Roses.  The Clifford family were one of the most prominent families among the northern English nobility of the fifteenth century; and by the marriages of his sisters John Clifford had links to some very important families of the time, including the earls of Devon.  He was orphaned at about twenty years of age when his father was slain at the first battle of the Wars of the Roses, the Battle of St Albans in 1455.  It was probably as a result of his father's death there that John became one of the strongest supporters of Queen Margaret of Anjou, consort of King Henry VI, who ended up as effective leader of the Lancastrian faction.  John Clifford had already achieved prominence in the north where, as an ally of the son of the earl of Northumberland, he took part in a feud against the Neville family, the Percy's natural rivals in Yorkshire.  This consisted of a series of armed raids, assaults and skirmishes, and included an ambush on one of the younger Nevilles' wedding party in 1453.  Historians have seen a direct connection between his involvement in the local feud in the north with the Nevilles, and his involvement in the national struggle against the duke of York, whom the Nevilles were closely allied with in the late 1450s.  Although this was supposedly a period of temporary peace between the factions, Clifford and his allies appear to have made numerous attempts to ambush the Neville and Yorkist lords. The Clifford family was a family of bankers, merchants and regenten of English descent who were active in Amsterdam during the sixteenth through eighteenth centuries.  The family originated in northern England, although the surname originated in the village of Clifford, Herefordshire.  Northern England was the home of the noble Clifford family, since Roger Clifford was born in Cumberland and died in Brough Castle in Westmorland.  There is no evidence that the Clifford banking family is descended from a nobleman named Clifford, who fought for William I of England. "The Boys of Barr na Sráide" is a well-known Irish song from a poem written by Irish poet Sigerson Clifford (1913–1985).  It is named after a street (Irish: "Barr na Sráide" , meaning "top of the street" ) in Cahersiveen in County Kerry, Ireland.  Clifford was born in Cork city, though both his parents came from Kerry. Rosamund Clifford (before 1150 – c. 1176), often called ""The Fair Rosamund"" or the ""Rose of the World"", was famed for her beauty and was a mistress of King Henry II of England, famous in English folklore. Charles Goodall (1671—May 11, 1689) is a minor English poet.  A student of Eton College and then Merton College, Oxford, he wrote a number of romantic and erotic poems referring to male students at said colleges.  In 1689, the year of his death, he put together a collection entitled "Poems and Translations" which contains 33 poems with male-male subject matter, eleven regarding women, and 13 to a mistress named 'Idera' (considered probably imaginary).  A number of the homoerotic poems have been rewritten to remove the same-sex subject matter. In mathematics, a Clifford algebra is an algebra generated by a vector space with a quadratic form, and is a unital associative algebra.  As "K"-algebras, they generalize the real numbers, complex numbers, quaternions and several other hypercomplex number systems.  The theory of Clifford algebras is intimately connected with the theory of quadratic forms and orthogonal transformations. Clifford algebras have important applications in a variety of fields including geometry, theoretical physics and digital image processing.  They are named after the English geometer William Kingdon Clifford.
Answer: Geoffrey of Anjou and Matilda