Question: What nationality are both Grosvenor and Hugh d'Avranches, Earl of Chester?

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Mary Anna Marten: Mary Anna Sibell Elizabeth Marten, OBE (1929–2010) was born Mary Anna Sibell Elizabeth Sturt on 12 September 1929 at Moor Critchel, the daughter of Napier Sturt, 3rd Baron Alington and Lady Mary Sibell Ashley-Cooper, daughter of the 9th Earl of Shaftesbury, sometime Lord Steward to the Household of George V & Queen Mary, by his wife Lady Constance Sibell Grosvenor (d 1957), a great friend of Queen Mary, dau of Earl Grosvenor, and sister of Hugh Grosvenor, 2nd Duke of Westminster.  She was god-daughter to Queen Elizabeth (later The Queen Mother), and in 1953 her son Napier was a page at the Coronation of Elizabeth II.

Richard Grosvenor, 1st Earl Grosvenor: Richard Grosvenor, 1st Earl Grosvenor (18 June 1731 – 5 August 1802), known as Sir Richard Grosvenor, Bt between 1755 and 1761 and as The Lord Grosvenor between 1761 and 1784, was a British peer, racehorse owner and art collector.  He was created Baron Grosvenor in 1761 and in 1784 became both Viscount Belgrave and Earl Grosvenor.

Hugh d'Avranches, Earl of Chester: Hugh d'Avranches (  1047  – 27 July 1101), also known as Hugh the Fat (French: "Hugues le Gros" ) or Hugh the Wolf (Latin: "Hugo Lupus" ), was the second Norman earl of Chester (2nd creation) and one of the great magnates of early Norman England.

Richard d'Avranches, 2nd Earl of Chester: Richard d'Avranches, 2nd Earl of Chester (1094 – 25 November 1120) was the son of Hugh, 1st Earl of Chester and Ermentrude of Clermont.

Grosvenor (surname): Grosvenor ( ) is a surname derived from Hugh Le Grand Veneur, a member of a Norman French family that aided William the Conqueror in 1066.  "Le Grand Veneur" literally means "the Master Huntsman" in French, an elevated title in William's 11th century French court.  Initially, Hugh was called Hugh Lupus.  Lupus was portly, and his townsmen gradually changed the appellation from "Le Grand Veneur", "the Master Huntsman," to "Le Gros Veneur", "the Fat Huntsman", and Hugh wore the epithet with pride.

Henry I, Count of Eu: Henry I, Count of Eu and Lord of Hastings (ca. 1075-12 July 1140), son of William II, Count of Eu, and his wife Helisende d'Avranches, sister of Hugh d'Avranches, Earl of Chester.  Count of Eu, Lord of Hastings.  Henry descended from Richard I, Duke of Normandy.  His father died in 1096, having revolted against the King William the Red.  Defeated, underwent a trial by combat that he lost to Geoffrey Baynard.  As a result, the king condemned him to blindness and emasculation.  He survived only a short time with his wounds.

Ranulf le Meschin, 3rd Earl of Chester: Ranulf le Meschin, 3rd Earl of Chester (1070−1129) was a late 11th- and early 12th-century Norman magnate based in northern and central England.  Originating in Bessin in Normandy, Ranulf made his career in England thanks to his kinship with Hugh d'Avranches - the earl of Chester, the patronage of kings William II Rufus and Henry I Beauclerc, and his marriage to Lucy, heiress of the Bolingbroke-Spalding estates in Lincolnshire.

Gerald Grosvenor, 6th Duke of Westminster: Major General Gerald Cavendish Grosvenor, 6th Duke of Westminster, (22 December 1951 – 9 August 2016) was a British landowner, businessman, philanthropist, Territorial Army general and hereditary peer.  He was the son of Robert George Grosvenor, 5th Duke of Westminster and Viola Grosvenor.  He was Chairman of the property company Grosvenor Group.  He is succeeded by his son, Hugh Grosvenor, 7th Duke of Westminster.

Hugh Grosvenor, 7th Duke of Westminster: Hugh Richard Louis Grosvenor, 7th Duke of Westminster (born 29 January 1991), styled as Earl Grosvenor until August 2016, is a British aristocrat, billionaire, businessman and landowner.  He is the third child and only son of Gerald Grosvenor, 6th Duke of Westminster and his wife Natalia Phillips Grosvenor, Duchess of Westminster.  He inherited the title of Duke of Westminster on 9 August 2016, on the death of his father.  The duke is estimated to be worth US$13 billion, making him the world's richest person aged under 30.

Robert Grosvenor, 1st Marquess of Westminster: Robert Grosvenor, 1st Marquess of Westminster, {'1': ", '2': ", '3': ", '4': "} (22 March 1767 – 17 February 1845) was the son of the 1st Earl Grosvenor, whom he succeeded in 1802 as 2nd Earl Grosvenor.  He was created Marquess of Westminster in 1831.  He was an English Member of Parliament (MP) and an ancestor of the modern-day Dukes of Westminster.  Grosvenor continued to develop the family's London estates, he rebuilt their country house, Eaton Hall in Cheshire where he also restored the gardens, and built a new London home, Grosvenor House.  He maintained and extended the family interests in the acquisition of works of art, and in horse racing and breeding racehorses.

Supporting paragraphs: Grosvenor (surname) Hugh d'Avranches, Earl of Chester
Answer: Norman French