Moreton was born in 1853, the fifth son of Thomas Frewen, MP for South Leicestershire. He was educated at Trinity College, Cambridge. Later, he was an Anglo-Irish writer on monetary reform, and served briefly as a Member of Parliament (standing at the December 1910 general election as an All-for-Ireland League MP for North East Cork). Moreton passed away in 1924.
: England and Wales Birth Registration Index record for Moreton Frewen:
Birth: Apr-May-Jun, 1853 in Rye, Sussex, England. 
1861 England Census; Brickwall House, Northiam, Sussex, England.
Thomas Frewen, 49, head, Cold Overton, Leicestershire, England
Helen Louisa Frewen, 39, wife, Ireland
Edward Frewen, 10, son, Casterton, Westmorland, England
Richard Frewen, 9, son, Cold Overton, Leicestershire, England
Moreton Frewen, 7, son, Northiam, Sussex, England
Anne Louisa Frewen, 5, daughter, Northiam, Sussex, England
Stephen Frewen, 3, son, Northiam, Sussex, England
Marianne G. Homan, sister-in-law, Ireland
additional listings for visitors and servants not included 
1880 US Census; 9 Jun 1880; Powder River, Carbon County, Wyoming, United States.
Richard Frewen Self M 28 England, single, farmer
Morton Frewen Brother M 27 England, single, farmer
Henry Crim Other M 28 Germany, single, servant-cook
Daniel Lynch Other M 31 Massachusetts, single, servant-work on farm
Antone Jajost Other M 12 Denmark, single, servant-table waiter
Otteny Jackson Other M 22 Indiana, single, servant-teamster
James Williams Other M 26 Illinois, single, servant-teamster
Oscar Oberrich Other M 26 Wisconsin, single, farm laborer
William Bloss Other M 28 Germany, single, farm laborer
Philip Reynolds Other M 28 Illinois, single, farm laborer 
1911 England Census; Claridges Hotel, Brook Street, Mayfair, London, England.
Moreton Frewen, 51, boarder, b. Northiam, Sussex, England, married 29 years. 
From FindAGrave memorial. No photos with dates; data, excluding burial location, is unsourced and information only.
Hugh Moreton Frewen was born 8 May 1853 in England and died 2 Sep 1924 (aged 71) in England. He is buried at St Mary's Churchyard, Northiam, Rother District, East Sussex, England.
“Unhorsed for good." That is how his nephew put it when Moreton Frewen was laid to rest. The Member of Parliment was better known as a cowboy, a cattle baron in fact. Moreton was born at Brickwall House, in the Frewen family since 1666. He was educated in the manner of the gentry, to which he belonged.
A marksman as a youth, being a younger son, he was to make his own way as a man. That way took him into far flung adventures. In 1879 Moreton sailed for the United States to make his fortune. He headed West, to Wyoming, and established himself in the business of cattle. He had built a large house of native timber, dubbing it Frewen Castle. The castle fell to fire, that financial calamity being one of many.
Moreton was described as a sublime failure. He was called a splendid pauper and nicknamed Mortal Ruin. Once in Wyoming, a shrewd dealer sold him a herd, drove them around the hill and sold him the same herd a second time.
He did well in marriage, being wed in 1881 to a striking New York socialite, Clara Jerome. Moreton was a difficult and unfaithful husband, including an affair with the popular actress, Lily Langtry. He returned to the United Kingdom in 1885. He had a home in London, and inherited 3000 acres in Ireland.
He became involved in politcal affairs and in 1910 was elected to The House of Commons. In 1922 Moreton lived at the ancient Brede Place. He had suffered a stroke and realizing his mortality, would sit in the shade of the yard and proclaim to anyone within hearing, "I am dying!", which he did in 1924.
Thomas Frewen 1811-1870
Helen Louisa Homan Frewen Unknown-1901
Clarita Jerome Frewen 1851-1935
Edward Frewen Unknown-1919
Richard Frewen Unknown-1896
Laton Frewen 1840-1856
Find A Grave, database and images (https://www.findagrave.com : accessed 21 May 2019), memorial page for Hugh Moreton Frewen (8 May 1853–2 Sep 1924), Find A Grave: Memorial #185019834, citing St Mary's Churchyard, Northiam, Rother District, East Sussex, England ; Maintained by George Seitz (contributor 40539541).
Wyoming, United States of America
Frewen Castle -- Near Sussex, Johnson County, Wyoming
"Two brothers, Moreton and Richard Frewen, left England bound for the wilds of Wyoming to hunt buffalo. Once they spotted the verdant Powder River country, however, they vowed to stay and invest in cattle. Moreton also invested in a wife, Clara Jerome of New York, aunt of Winston Churchill. Erecting an exquisite two-story log “castle”, the Frewens filled the home with every known luxury. Locals dubbed the home Frewen Castle. English hunting parties and high teas filled their social calendar, and ladies who visited were treated to hothouse bouquets delivered on horseback. British nobility graced the castle with their presence, and it was a magical kingdom. Then, the disastrous winter of 1886-87 devastated the cattle herd. Moreton suffered financial losses from which he could not recover. He and his family returned to England, where he deposited Clara and their three children in an English countryside while he travelled [sic] extensively. Very little remains of the Frewen Castle today."
↑ “United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MWM2-SYS : 14 September 2017), Morton Frewen in entry for Richard Frewen, 1880; citing enumeration district ED 19, sheet 143D, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d), roll 1454; FHL microfilm 1,255,454.