Question: Who was Vaughan Williams' friend who helped collect folk songs in southern England and was a founding father of the folk-song revival in England in the early 20th century?

full_context: Document 1: Fantasia on a Theme by Thomas Tallis: Fantasia on a Theme by Thomas Tallis, also known as the Tallis Fantasia, is a work for string orchestra by the British composer Ralph Vaughan Williams. It was composed in 1910 and performed for the first time on 10 September that year at Gloucester Cathedral for the Three Choirs Festival. Vaughan Williams himself conducted, and the composition proved to be a major success. He revised the work twice, in 1913 and 1919. Performances generally run between 14 and 16 minutes.
Document 2: Sleigh Ride: "Sleigh Ride" is a popular light orchestral Christmas music standard composed by Leroy Anderson. The composer had the original idea for the piece during a heat wave in July 1946 and finished the work in February 1948. It was originally an instrumental piece; the lyrics, about someone asking another to join them for a ride in a sleigh, were written by Mitchell Parish in 1950. The orchestral version was first recorded in 1949 by Arthur Fiedler and the Boston Pops Orchestra. Sleigh Ride was a hit record on RCA Victor Red Seal 49-0515 (45 rpm) / 10-1484 (78 rpm), and has become a signature song for the orchestra. The 45 rpm version was originally issued on red vinyl. The Pops has also recorded the song with John Williams, their conductor from 1979 to 1995, and Keith Lockhart, their current conductor.
Document 3: Cecil Sharp: Cecil James Sharp (22 November 1859 – 23 June 1924) was the founding father of the folk-song revival in England in the early 20th century.
Document 4: Lucy Broadwood: Lucy Etheldred Broadwood (9 August 1858 – 22 August 1929) was an English folksong collector and researcher during the late 19th and early 20th centuries. As one of the founder members of the Folk-Song Society and Editor of the Folk Song Journal, she was one of the main influences of the English folk revival of that period. She was an accomplished singer, composer, piano accompanist, and amateur poet. She was much sought after as a song and choral singing adjudicator at music festivals throughout England, and was also one of the founders of the Leith Hill Music Festival in Surrey.
Document 5: Christmas Oratorio: The Christmas Oratorio (German: "Weihnachts-Oratorium" ), BWV 248 , is an oratorio by Johann Sebastian Bach intended for performance in church during the Christmas season. It was written for the Christmas season of 1734 and incorporates music from earlier compositions, including three secular cantatas written during 1733 and 1734 and a now lost church cantata, BWV 248a. The date is confirmed in Bach's autograph manuscript. The next performance was not until 17 December 1857 by the Sing-Akademie zu Berlin under Eduard Grell. The "Christmas Oratorio" is a particularly sophisticated example of parody music. The author of the text is unknown, although a likely collaborator was Christian Friedrich Henrici (Picander).
Document 6: Carol of the Old Ones: "Carol of the Old Ones" is a song originally published in the 1988 HPLHS Solstice Carol Songbook, released by the H. P. Lovecraft Historical Society. With lyrics written by Andrew Leman, it is sung and performed to the tune of "Carol of the Bells" by Mykola Dmytrovych Leontovych (itself sung to the tune of Shchedryk), with soprano lead vocals and four-part harmony at various points in the song. The song is performed by The Dagon Tabernacle Choir; the performers' names are Rebecca Marcotte, Digby Dolmen, J.D. Titan, and Walter Forsythe. It can be found on the album "A Very Scary Solstice".
Document 7: William Sharp (homeopath): William Sharp (1805–1896) was an English surgeon and physician. Sharp is credited with first advocating the establishment of local museums in Britain and for putting science on the curricula of British public schools. He was the first science teacher in a British public school and an early advocate of homoeopathy.
Document 8: Fantasia on Christmas Carols: Fantasia on Christmas Carols is a 1912 work for baritone, chorus, and orchestra by the English composer Ralph Vaughan Williams. First performed at the 1912 Three Choirs Festival at Hereford Cathedral, the work is a single movement of roughly twelve minutes which consists of the English folk carols "The truth sent from above", "Come all you worthy gentlemen" and "On Christmas night all Christians sing" (i.e. the Sussex Carol), all folk songs collected in southern England by Vaughan Williams and his friend Cecil Sharp a few years earlier. These are interposed with brief orchestral quotations from other carols, such as "The First Nowell". The early work remains popular with choral societies, and is sometimes paired with his longer Christmas work "Hodie" of 1954. There is also a version of the "Fantasia" which replaces the orchestra with strings and organ. A purely orchestral version, in which the solo vocal and choral parts were 'cued in' on the orchestral instruments, was performed in Studio 8H, New York, on 19 December 1943 by the NBC Symphony conducted by Leopold Stokowski. The broadcast of this unpublished version, which was presumably arranged by the conductor, has been released on a 'Guild Historical' CD and is also uploaded on YouTube.
Document 9: The Full English (folk music archive): The Full English launched in 2013 and is an ongoing English Folk Dance and Song Society (EFDSS) project to create a searchable digital archive of English folk song collections from the early 20th century, thereby preserving and improving the accessibility of these resources. The project is supported by the Heritage Lottery Fund, The Folklore Society, the National Folk Music Fund and the English Miscellany Folk Dance Group. An offshoot of the archive, also in 2013, was an album and concert tour under The Full English name by a collective of UK folk singers.
Document 10: Folk music of England: The folk music of England is traditionally based music, which has existed since the later medieval period. It is often contrasted with courtly, classical and later commercial music. Folk music has been preserved and transmitted orally, through print and later through recordings. The term is used to refer to English traditional music and music composed, or delivered, in a traditional style. English folk music has produced or contributed to several important musical genres, including sea shanties, jigs, hornpipes and dance music, such as that used for Morris dancing. It can be seen as having distinct regional and local variations in content and style, particularly in areas more removed from the cultural and political centres of the English state, as in Northumbria, or the West Country. Cultural interchange and processes of migration mean that English folk music, although in many ways distinctive, has particularly interacted with the music of Scotland. It has also interacted with other musical traditions, particularly classical and rock music, influencing musical styles and producing musical fusions, such as British folk rock, folk punk and folk metal. There remains a flourishing sub-culture of English folk music, which continues to influence other genres and occasionally to gain mainstream attention.
Document 11: Ralph Vaughan Williams: Ralph Vaughan Williams {'1': ", '2': ", '3': ", '4': "} ( 12 October 1872– 26 August 1958) was an English composer. His works include operas, ballets, chamber music, secular and religious vocal pieces and orchestral compositions including nine symphonies, written over nearly fifty years. Strongly influenced by Tudor music and English folk-song, his output marked a decisive break in British music from its German-dominated style of the 19th century.
Document 12: Mary Sands: Mary Bullman Sands (April 8, 1872 – April 2, 1949), from Allanstand in Madison County, North Carolina, was a singer of old traditional ballads during the early part of the 20th century. She was known locally as "Singing Mary" due to her singing talent and extensive knowledge of the words and melodies of many old-time traditional songs that had been passed down through previous generations. In 1916, English folklorist Cecil Sharp visited Madison County to collect and record traditional folk songs being sung in America that would have originated generations earlier in the British Isles. Sands sang 25 songs for him, 23 of which he included in his book, "English Folk Songs from the Southern Appalachians".
Document 13: Seventeen Come Sunday: "Seventeen Come Sunday" is an English folk song (Roud 277, Laws O17) which was used in the first movement of Ralph Vaughan Williams' "English Folk Song Suite" and a choral version by Percy Grainger (1912). The words were first published between 1838 and 1845.
Document 14: Somerset Carol: Come all you worthy gentlemen, sometimes referred to as the Somerset Carol, is an English folk carol of unknown authorship. It was collected from a Mr. Rapsey, of Bridgwater during the English Folk-song revival at the turn of the 20th century by Cecil Sharp. It was first published in 1905 in Sharp and Marson's "Folk songs from Somerset".
Document 15: Six Studies in English Folk Song: Six Studies in English Folk Song is a piece of chamber music written by English composer Ralph Vaughan Williams in 1926. It is a collection of six English folk songs set for cello and piano. Each song follows the same format: presentation of the tune in the solo line, followed by a full iteration of the folk song in the piano with an ornamented solo line.
ground_truth: Cecil Sharp