Question: Where did As I look ahead, I am filled with foreboding; like the Roman, I seem to see the River Tiber foaming with much blood""). come from?

full_context: Document 1: Like the Roman: The Life of Enoch Powell: Like the Roman: The Life of Enoch Powell is a 1998 book by the English writer Simon Heffer. It is a biography of the politician Enoch Powell. The title is taken from Powell's 1968 Rivers of Blood speech when Powell quoted Virgil's "Aeneid": "As I look ahead, I am filled with foreboding; like the Roman, I seem to see the River Tiber foaming with much blood".
Document 2: Edward Gibbon: Edward Gibbon FRS ( ; 8 May 173716 January 1794) was an English historian, writer and Member of Parliament. His most important work, "The History of the Decline and Fall of the Roman Empire", was published in six volumes between 1776 and 1788 and is known for the quality and irony of its prose, its use of primary sources, and its open criticism of organised religion.
Document 3: Rivers of Blood speech: On 20 April 1968, British Member of Parliament Enoch Powell addressed a meeting of the Conservative Political Centre in Birmingham, UK. His speech strongly criticised Commonwealth immigration to the United Kingdom and the then-proposed Race Relations Bill, and became known as the "Rivers of Blood" speech, although Powell always referred to it as "the Birmingham speech". The expression "rivers of blood", which did not appear in the original speech, is an allusion to a line from Virgil's "Aeneid" quoted by Powell (""As I look ahead, I am filled with foreboding; like the Roman, I seem to see the River Tiber foaming with much blood"").
Document 4: Aeneid: The Aeneid ( ; Latin: "Aeneis" ] ) is a Latin epic poem, written by Virgil between 29 and 19 BC, that tells the legendary story of Aeneas, a Trojan who travelled to Italy, where he became the ancestor of the Romans. It comprises 9,896 lines in dactylic hexameter. The first six of the poem's twelve books tell the story of Aeneas's wanderings from Troy to Italy, and the poem's second half tells of the Trojans' ultimately victorious war upon the Latins, under whose name Aeneas and his Trojan followers are destined to be subsumed.
Document 5: Nigel Hastilow: Nigel Hastilow (born 1956) is a journalist, author, businessman and politician. He is a former editor of the "Birmingham Post" and was Conservative Party candidate for Birmingham Edgbaston in the 2001 general election. In April 2007, Hastilow was selected a prospective parliamentary candidate (PPC) for the Conservative Party for the Halesowen and Rowley Regis constituency but was dumped after he received criticism about a newspaper column he wrote for the "Express & Star" which included the statement "Enoch Powell was right", sparking a national controversy about immigration and racism.
Document 6: John Betjeman: Sir John Betjeman, CBE ( ; 28 August 190619 May 1984) was an English poet, writer, and broadcaster who described himself in "Who's Who" as a "poet and hack". He was Poet Laureate of the United Kingdom from 1972 until his death.
Document 7: Enoch Powell: John Enoch Powell, MBE (16 June 1912 – 8 February 1998 ) was a British politician, classical scholar, philologist, and poet. He served as a Conservative Member of Parliament (MP, 1950–74), Ulster Unionist Party (UUP) MP (1974–87), and Minister of Health (1960–63).
Document 8: Blood, toil, tears, and sweat: The phrase "blood, toil, tears and sweat" became famous in a speech given by Winston Churchill to the House of Commons of the Parliament of the United Kingdom on 13 May 1940.
Document 9: First televised speech in the UK Parliament: The first televised speech in the House of Commons of the United Kingdom was made by Ian Gow, the Conservative Member of Parliament for Eastbourne, on 21 November 1989.
Document 10: Suicide in the Trenches: “Suicide in the Trenches,” by the English poet Siegfried Sassoon (1886-1967), is one of the many poems Sassoon composed in response to World War I. It reflects his own notable service in that especially bloody conflict. Sassoon was a brave and gallant upper-class officer who eventually opposed the war, but he never lost his admiration for the common soldiers who had to fight it. Sassoon felt contempt for the political leaders and civilian war hawks who, safe in their power and comfort, sent young men off to die in huge battles that seemed futile and pointless. It was first published February 23, 1918 in "Cambridge Magazine", then in Sassoon's collection: "Counter-Attack and Other Poems". The poem is written in iambic tetrameter and consists of twelve lines in three stanzas.
Document 11: Agricola (book): The Agricola (Latin: "De vita et moribus Iulii Agricolae" , lit. On the life and character of Julius Agricola) is a book by the Roman historian Tacitus, written  AD 98 , which recounts the life of his father-in-law Gnaeus Julius Agricola, an eminent Roman general and Governor of Britain from AD 77/78 - 83/84. It also covers, briefly, the geography and ethnography of ancient Britain. As in the "Germania", Tacitus favorably contrasts the liberty of the native Britons to the corruption and tyranny of the Empire; the book also contains eloquent and forceful polemics against the rapacity and greed of Rome.
Document 12: Radio Enoch: Radio Enoch was a pirate radio station in the United Kingdom, operating out of the West Midlands, homeland of its namesake, Enoch Powell. Radio Enoch professed a socially right-wing viewpoint, and also extolled the virtues of capitalism and privatisation. The manager claimed it operated as an unlicensed station because its views on race and immigration would prevent it from being able to broadcast in what it deemed a "socialist" media. The station also expressed support for the white minority rule governments of Rhodesia and South Africa. The station was launched in 1978, broadcasting hour-long shows monthly.
Document 13: Henry Petowe: Henry Petowe (1575/6–1636?) was a minor Elizabethan poet, best known today, perhaps, for "The Second Part of "Hero and Leander", Containing their Further Fortunes," his sequel to Christopher Marlowe's "Hero and Leander".
Document 14: Powellism: Powellism is the name given to the political views of Conservative and Ulster Unionist politician Enoch Powell. They derive from his High Tory and libertarian outlook.
Document 15: Seamus Heaney: Seamus Justin Heaney, ( ; 13 April 1939 – 30 August 2013) was an Irish poet, playwright, translator and lecturer from Northern Ireland. He received the 1995 Nobel Prize in Literature.
ground_truth: from Powell's 1968 Rivers of Blood speech