Question: The Abbey of Saint-Étienne was founded by a descendant of who?

Context paragraphs:
William the Conqueror: William I (c. 1028 – 9 September 1087), usually known as William the Conqueror and sometimes William the Bastard, was the first Norman King of England, reigning from 1066 until his death in 1087.  A descendant of Rollo, he was Duke of Normandy (as Duke William II) from 1035 onward.  After a long struggle to establish his power, by 1060 his hold on Normandy was secure, and he launched the Norman conquest of England six years later.  The rest of his life was marked by struggles to consolidate his hold over England and his continental lands and by difficulties with his eldest son.

Bassac Abbey: Bassac Abbey (French: "Abbaye Saint-Étienne de Bassac" ) is an 11th-century Romanesque style abbey in Bassac, Charente and part of the Ancient Diocese of Saintes .  The church was founded in 1002 by Wardrade Loriches, count of la Marche and first known Lord of Jarnac.  It was built to 1015 by Angel de Grimoard, Bishop of Angoulême, and his brother Iso, Bishop of Saintes.  In 1095 it was made subservient to the Abbey of Saint-Jean-D'Angely by Pope Urban II; it regained its independence in 1246.  Bassac Abbey was largely reconstructed under Guillaume de Vibrac, Abbot from 1247 to 1286.

Abbey of Saint Gall: The Abbey of Saint Gall (German: Abtei St. Gallen ) is a dissolved abbey (747–1805) in a Roman Catholic religious complex in the city of St. Gallen in Switzerland.  The Carolingian-era monastery has existed since 719 and became an independent principality between 9th and 13th centuries, and was for many centuries one of the chief Benedictine abbeys in Europe.  It was founded by Saint Othmar on the spot where Saint Gall had erected his hermitage.  The library at the Abbey is one of the richest medieval libraries in the world.  The city of St. Gallen originated as an adjoining settlement of the abbey.  Following the secularization of the abbey around 1800 the former Abbey church became a Cathedral in 1848.  Since 1983 the whole remaining abbey precinct has been a UNESCO World Heritage Site.

AS Saint-Étienne: Association Sportive de Saint-Étienne Loire (] ; commonly known as AS Saint-Étienne, ASSE, or simply Saint-Étienne) is a French association football club based in Saint-Étienne.  The club was founded in 1933 and currently plays in Ligue 1, the top division of French football.  Saint-Étienne plays its home matches at the Stade Geoffroy-Guichard.  The team is managed by Óscar García and captained by Loïc Perrin, who started his career at the club in 1996.  Saint-Étienne is known as "Les Verts" meaning "the Greens" due to its home colours.

Vauluisant Abbey: Vauluisant Abbey, near Courgenay in the canton of Brienon-sur-Armançon, Yonne, France, is a Cistercian abbey founded in 1127 by a group of monks from the abbey of Preuilly (Seine-et-Marne) who came to settle between the forest of Othe and the forest of Lancy, an area near the borders of Ile-de-France, Champagne and Burgundy that had come to be far from human habitation.  They diverted the waters of the little River Alain and by 1 April 1129, works were far enough advanced for Henri Sanglier, the archbishop of Sens, to consecrate the modest oratory.  By 1140 Vauluisant was fully operational.  The abbey church was consecrated in 1149.  In the second half of the 12th century, granges were established to cultivate abbey lands far from the abbey itself, at Beauvais, Toucheboeuf, Livanne, Cérilly, Armentières, worked by lay brothers who lived communally.  Ironworks were established, fuelled by the dense woodlands, and tileworks, whose kilns were also fired by forest timber.  The energetic Cistercians of Vauluisant produced more than the abbey needed; the surplus was sold in the market towns of Troyes and Provins, where the abbots retained domiciles, and at the cathedral town of Sens.

Leicester Abbey: The Abbey of Saint Mary de Pratis, more commonly known as Leicester Abbey, was an Augustinian religious house in the city of Leicester, in the English Midlands.  The abbey was founded in the 12th century by the Robert de Beaumont, 2nd Earl of Leicester, and grew to become the wealthiest religious establishment within Leicestershire.  Through patronage and donations the abbey gained the advowsons of countless churches throughout England, and acquired a considerable amount of land, and several manorial lordships.  Leicester Abbey also maintained a cell (a small dependent daughter house) at Cockerham Priory, in Lancashire.  The Abbey's prosperity was boosted though the passage of special privileges by both the English Kings and the Pope.  These included an exemption from sending representatives to parliament and from paying tithe on certain land and livestock.  Despite its privileges and sizeable landed estates, from the late 14th century the abbey began to suffer financially and was forced to lease out its estates.  The worsening financial situation was exacerbated throughout the 15th century and early 16th century by a series of incompetent, corrupt and extravagant abbots. By 1535 the abbey's considerable income was exceeded by even more considerable debts.

AS Saint-Étienne (women): Association Sportive de Saint-Étienne Loire Féminin (] , commonly known as AS Saint-Étienne) is a French football club based in Saint-Étienne which plays in D1 Féminine.  The club is the women's side of the French football club of the same name and was founded in 1977 under the name Racing Club de Saint-Étienne.  The current name was adopted following the 2008–09 season as the club RC Saint-Étienne merged with their men's side.

Abbot of Melrose: The Abbot and then Commendator of Melrose was the head of the monastic community of Melrose Abbey, in Melrose in the Borders region of Scotland.  The abbots of the earlier Northumbrian foundation from Lindisfarne are not included here.  The second abbey was founded in 1136 on the patronage of David I ("Dabíd mac Maíl Choluim"), King of Scots, by Cistercian monks from Rievaulx Abbey, Yorkshire.  Control of the abbey was secularized in the 16th century and after the accession of James Stewart, the abbey was held by commendators.  The last commendator, James Douglas of Lochleven, resigned the abbacy to William Douglas, 6th Earl of Morton (his nephew) in December 1606, and the abbey itself to the king in 1608.  The abbey (or most of its lands) was then erected into a secular lordship for viscount Haddington, John Ramsay, who in 1609 was created "Lord Melrose".  Lochleven however resumed the title of commendator in 1613 until his death in 1620.

Saint-Étienne Mine Museum: The "Saint-Étienne Mine Museum" is a French museum founded in 1991 in the city of Saint-Étienne in the French department of the Loire situated in the Rhône-Alpes region.  The site is registered as an historical monument since 2011

Abbey of Saint-Étienne, Caen: The Abbey of Saint-Étienne, also known as Abbaye aux Hommes ("Men's Abbey") by contrast with the Abbaye aux Dames ("Ladies' Abbey"), is a former Benedictine monastery in the French city of Caen, Normandy, dedicated to Saint Stephen.  It was founded in 1063 by William the Conqueror and is one of the most important Romanesque buildings in Normandy.

Supporting paragraphs: Abbey of Saint-Étienne, Caen William the Conqueror
Answer: Rollo