Sir Robert Walpole and Horace Walpole - Arlington Street, London UK - Blue Plaques on Waymarking.com

The BBC History website has an article about Sir Robert Walpole that tells us:

Walpole was a British Whig statesman, considered to the first holder of the office of prime minister, who dominated politics in the reigns of George I and George II.

Robert Walpole was born on 26 August 1676 in Houghton, Norfolk into a wealthy landowning family. He was educated at Cambridge University and in 1701 became member of parliament for Castle Rising in Norfolk, where his father had previously been MP. He rose rapidly, becoming a member of the Admiralty Board, secretary of war and, in 1709, treasurer of the navy. His rise was temporarily halted by the Tories, who came into power in 1710. In 1712, they accused him of corruption and he was briefly imprisoned.

In 1714, George I came to the throne. George distrusted the Tories, whom he believed opposed his right to the throne, and as a result the Whigs were in the ascendant again. In 1715, Walpole became first lord of the treasury and chancellor of the exchequer. He resigned in 1717 after disagreements within his party but in 1720 was made paymaster general. He avoided the scandal that surrounded the collapse of the South Sea Company and was subsequently appointed first lord of the treasury and chancellor of the exchequer again. In this position he effectively became prime minister, although the term was not used at the time. He remained in this position of dominance until 1742.

Walpole consolidated Whig power through a system of royal patronage. He pursued a policy of peace abroad, low taxation and reducing the national debt and he knew the importance of keeping parliament on his side. He was also accused of bribery and corruption in his efforts to retain power. After George I's death in 1727, Walpole was briefly superseded by George II's favourite, Spencer Compton, but succeeded in returning himself to favour, partly through the support of the new queen, Caroline. In 1735, George II made Walpole a gift of 10 Downing Street, now the permanent London residence of the British prime minister.

Opposition eventually began to develop within Walpole's own party, and a trade dispute with Spain was used by his critics to force him to declare war in 1739, known as the War of Jenkins' Ear. A poor general election result in 1741 made his position more unstable. A number of Whig politicians opposed Walpole's conduct of the war and he resigned in February 1742. He was created earl of Orford in the same year and continued to maintain influence over George II. Walpole died on 18 March 1745.

The Encyclopaedia Britannica website has an article about Horace Walpole that tells us:

Horace Walpole, 4th earl of Orford, original name Horatio Walpole    (born Sept. 24, 1717, London—died March 2, 1797), English writer, connoisseur, and collector who was famous in his day for his medieval horror tale The Castle of Otranto, which initiated the vogue for Gothic romances. He is remembered today as perhaps the most assiduous letter writer in the English language.

The youngest son of the prime minister Sir Robert Walpole, he was educated at Eton and at King’s College, Cambridge. In 1739 he embarked with his Eton schoolmate, the poet Thomas Gray (later to write “An Elegy Written in a Country Church Yard”), on a grand tour of France and Italy, in the midst of which they quarrelled and separated. They were later reconciled, and Walpole remained throughout his life an enthusiastic admirer of Gray’s poetry. On his return to England in 1741, Walpole entered Parliament, where his career was undistinguished, although he attended debates regularly until 1768. In 1791 he inherited the peerage from a nephew, a grandson of Robert Walpole. He remained unmarried, and on his death the earldom became extinct.

The most absorbing interests of his life were his friendships and a small villa that he acquired at Twickenham in 1747 and transformed into a pseudo-Gothic showplace known as Strawberry Hill. Over the years he added cloisters, turrets, and battlements, filled the interior with pictures and curios, and amassed a valuable library. The house was open to tourists and became widely known in Walpole’s own lifetime. He established a private press on the grounds, where he printed his own works and those of his friends, notably Gray’s Odes of 1757. Strawberry Hill was the stimulus for the Gothic revival in English domestic architecture.

Walpole’s literary output was extremely varied. The Castle of Otranto (1765), which was first published anonymously, succeeded in restoring the element of romance to contemporary fiction. In it he furnished the machinery for a genre of fiction wherein the wildest fancies found refuge. He also wrote The Mysterious Mother (1768), a tragedy with the theme of incest; amateur historical speculations such as Historic Doubts on the Life and Reign of King Richard the Third (1768); and a genuine contribution to art history, Anecdotes of Painting in England, 4 vol. (1762–71).

His most important works were intended for posthumous publication. His private correspondence of some 4,000 letters constitutes a survey of the history, manners, and taste of his age. Walpole revered the letters of Mme de Sévigné (1626–96) and, following her example, consciously cultivated letter writing as an art. His most substantial correspondence was with Horace Mann, a British diplomat whom Walpole met on his grand tour and with whom he maintained contact for 45 years, although the two never met again. Walpole’s correspondence, edited by W.S. Lewis and others, was published in 48 volumes (1937–83).

Walpole also left Memoirs (first published 1822–59) of the reigns of George II and III, a record of political events of his time.