The seat of the Herbert family, earls of Powis, the castle is known for its formal gardens and for its interiors, the former having been described as "the most important", and the latter "the most magnificent", in the country.

Gruffydd was prince of the ancient Kingdom of Powys and maintained an alliance with the English king Edward I during the struggles of the later 13th century.

The Herberts remained Roman Catholic until the 18th century and, although rising in the peerage to earls, marquesses and Jacobite dukes of Powis, suffered periods of imprisonment and exile.

Despite these setbacks, they were able in the late 17th and early 18th centuries to transform Powis from a border fortress into an aristocratic country house, and surround it with one of the very few extant examples of a British Baroque garden.

[4] Domen Castell, a motte-and-bailey near the modern railway station, is considered the most likely site of Cadwgan's castle, although it is uncertain whether it was completed as he was assassinated the same year.

[13] At the end of Edward I's conquest of Wales in 1282–83, the king permitted Gruffydd to rebuild his castle at Welshpool as a reward for his loyalty.

[17] The Charltons continued to live at Powis until the fifteenth century when two daughters, Joyce Tiptoft and Joan Grey inherited the castle and estates.

[19] Sir Edward's wife was a Roman Catholic and the family's allegiance to Rome and to the Stuart kings was to shape its destiny for over a century.

John Byng, 5th Viscount Torrington, a diarist and traveller who chronicled his journeys into Wales in the 1780s and 1790s, described the castle in 1784, "In the gardens not even the fruit is attended to; the balustrades and terraces are falling down, and the horses graze on the parterres!!!

George Lyttelton, the politician, poet and essayist, recorded his impressions in 1756, "About £3,000 laid out upon Powis Castle would make it the most august place in the Kingdom.

[30] Edward Herbert served in a range of administrations as an Anti-Catholic Tory, his speeches in the House of Commons being "cautious and pertinent, although marred by dull delivery".

In honour of his great-grandfather, the earl was offered the viceroyalty of India by Benjamin Disraeli but declined, writing "Not worth considering.

[g][36] The 4th earl's wife, Violet (nee Lane-Fox), undertook the final transformation of the gardens of Powis Castle, which she felt had the potential to be "the most beautiful in England and Wales".

[44] The Trust has undertaken a number of major works of restoration during its ownership, including the Marquess Gate,[45] the Grand Staircase,[46] and the sculpture of Fame in the Outer Courtyard.

Originally located in the water gardens, the piece seems to have been struck from the same mould as the Pegasus and Fame supplied by van Nost between 1705 and 1716 to Sir Nicholas Shireburn at Stonyhurst, Lancashire.

[55] They contain murals and ceiling paintings by Antonio Verrio and Gerard Lanscroon; a collection of Elizabethan and Jacobean family portraits mainly of members of the Herberts of Chirbury, who inherited the castle in the early 18th century; Carolean furnishings of notable richness and quality; and items from the picture and Indian collections of Robert Clive.

[56] The early 20th-century redevelopment and redecoration undertaken by George Bodley was sensitively handled, Scourfield and Haslam consider it "appropriate and finely executed",[57] and it is the only remaining, unaltered, example of his decorative approach.

The report's authors concluded that there was not a direct link, but emphasised the challenge of balancing the needs of visitors with the requirement to maintain historic fabrics.

The chimneypieces in the room were copied from examples in the Victoria and Albert Museum, and the ceiling from the Reindeer Inn, a public house in Banbury, both at the Earl's suggestion.

[73] When Robert Clive returned to England, his fortune of some £234,000 (£23 million today), made him the richest self-made man in Europe.

[m][51] These include Tipu Sultan's magnificent state tent, made of painted chintz; gold and bejewelled tiger's head finials from Tipu's throne; two cannons that are today positioned on either side of the castle entrance, and textiles, armour, weapons, bronzes, silver pieces, and collections of jade and ivory.

[30] The Clive Museum, opened in 1987 next to the ballroom in the North Range,[75] has been the focus of controversy in the 21st century, because of the raised awareness of the links between country house collections and colonialism, as a result of the Black Lives Matter movement.

[76] The National Trust has committed to supporting reinterpretation of the South Asian collection and in 2020 commissioned a research project in association with the Ashmolean Museum to investigate its history, contents and provenance.

[106] Although their exact dating is uncertain, the terraces were hewn from the rock at some point between the 1670s and 1705 under the direction of William Winde and later Adrian Duvall, a French gardener from Rouen.

John Bridgeman, a guest in that year, wrote "the waterworks and fountains are much beyond anything I ever saw, the cascade has two falls of water which concludes in a noble Bason (sic).

The Earl rejected his advice regarding the terraces, although the lowest two were reduced to earthen banks, but permitted the replacement of the water garden with the Great Lawn.

[106] The water garden had comprised a series of pools and fountains, interspersed with flower beds and decorated with an array of statuary, a number of which, such as the Fame and the Hercules were relocated to different sites on the estate.

When built this was heated and was open to the elements, but in the early 20th century the arcade was enclosed with windows and a door case moved from the main entrance to the keep in the Outer Courtyard.

[118] The kitchen garden had previously been concealed from the castle by a bank of elm trees, but these were brought down in a storm in 1912, exposing a view of the greenhouses which appalled the Countess.

"I am greeted every day by the repulsive sight of the detestable little [hot]houses which stare in their naked horror up at the beautiful terraces and the grand old castle towering above.