Althorp

Domesday Book recorded Olletorp in 1086 with a population of ten. Fifty people over 14 paid poll tax there in 1377, but the village shrank and by 1505 no tenants were living there at all. John Spencer, whose family's sheep-rearing business was earning large profits, bought Althorp from the Catesby family in 1508 for £800, and died in 1522 leaving it to his youngest son, Sir William Spencer, High Sheriff of Northamptonshire.

Anne of Denmark and Prince Henry broke their journey from Edinburgh to Windsor at Althorp on 25 June 1603, weeks before Robert Spencer was created Baron Spencer of Wormleighton; the queen was met with an entertainment scripted by Ben Jonson in which the Fairy Queen Mab gave her a jewel. Charles I visited during his reign, for which the drawing room was built, the main hall enlarged and £1,300 spent on the banquet. Robert's grandson Henry Spencer fought at Edgehill in 1642, was made Earl of Sunderland on 8 June 1643, and was killed by a cannonball at the First Battle of Newbury that 20 September, aged 23.

Robert Spencer, 2nd Earl of Sunderland, inherited at two years old and built the present house in 1688; the French landscape architect André Le Nôtre had been commissioned to lay out the park and grounds in the 1660s. John Evelyn called it that year "a noble uniform pile in form of a half H". In the same year his bad temper and his reputation as a ruthless advocate of absolute monarchy made him enemies enough to force him to flee to the Netherlands; he lived secluded at Althorp from his retirement from public life in December 1697 until his death in 1702.

John Spencer celebrated his 21st birthday with a ball on 20 December 1755, during which he secretly married the 18-year-old Margaret Georgiana Poyntz. He built Spencer House in London and was created Viscount Spencer in 1761 and Earl Spencer in 1765. From 1788 the architect Henry Holland encased the old red brick in mathematical tiles brought from Ipswich and added four Corinthian pilasters of Roche Abbey stone.

George John, 2nd Earl Spencer, who held Althorp from 1783, built one of the largest private libraries in Europe, more than 100,000 books by the 1830s, and founded the Roxburghe Club in 1812. He died in 1834 leaving £500,000 of debt to his son the 3rd Earl, who repaid it all by his death in 1845, living mostly at his far cheaper farm at Wiseton.

John Spencer, 5th Earl Spencer, in financial trouble, sold much of the library in 1892 to Enriqueta Rylands, who was building the University of Manchester Library. Albert Spencer, 7th Earl, who inherited in 1922, sold paintings to pay debts: in the 1930s a Hans Holbein portrait of Henry VIII went for £10,000 to finance his son's education. Unlike many British country houses taken over in the Second World War, Althorp was left untouched, Albert seeing to it that the military used the stables; a Wellington bomber crashed near the ice house, killing all its crew. He opened the estate to the public in 1953 to mitigate taxation.

Under Edward John, 8th Earl Spencer, who inherited in 1975, about 20% of the furnishings were sold, including eleven Van Dycks and nearly every religious painting, drawing severe public criticism. Charles Spencer, 9th Earl, inherited in 1992 with the estate losing £400,000 a year; a restoration of roof, stonework and tiles followed in 2009, about £10 million on the roof alone, and an auction of attic and cellar contents in 2010 raised £21 million.

Diana, Princess of Wales, who lived at Althorp from her parents' divorce until her marriage, died on 31 August 1997 and was buried on an island in the ornamental Round Oval lake, made by William Milford Teulon in 1868. Her brother said the island was chosen because the water would "act as a buffer against the interventions of the insane and ghoulish". The Bishop of Peterborough consecrated the ground before the burial, and the grave is marked by a white plinth and urn.

The house has been Grade I listed since 1954 and the park and garden Grade II* since 1984, and the house and estate open to the public from 1 July to 30 August. A Doric temple across the water, first commissioned by the 2nd Earl Spencer in thanks for the victory at the Battle of the Nile, carries her name and Charles Spencer's funeral tribute; Dan Pearson planted 36 oaks along the access road for the years of her life. An exhibition devoted to her in the Grade II* listed stable block opened in 1998 and closed in August 2013, its contents packed up to be given to her sons.