Introduction: The castle was a Welsh stronghold, probably of Owain Cyfeiliog and his heirs, from c1170, and parts of the surviving structure are thought to date from the late C12- early C13. The castle was sacked c1275, and in 1286, Owain ap Gruffydd ap Gwenwynwyn, Prince of Powys, paid homage to Edward I as Baron de la Pole. A substantial programme of rebuilding followed - the layout, and much of the structure of the present buildings were determined in this work of c1300.
Sir Edward Herbert acquired the castle in 1587, and initiated the creation of a country house from a castle. The first phase of a substantial Baroque remodelling was begun immediately following the restoration of Charles II (Powis had fallen in a siege of 1644 and was not returned to the Herbert family until the Restoration). William, Third Lord Powis who inherited the title in 1867 (and was created Earl in 1674,
Marquis in 1685), was exiled with James II in 1688 - and although the Herbert's were not formally re-instated at Powis until 1722, a major programme of work on the castle and gardens was initiated by the family during this period, extending the scope of the Baroque remodelling.
Minor works were carried out during the C18, but the castle was suffering from neglect by the latter years of the century: in 1771, Thomas Farnolls Prichard, architect, of Shrewsbury, was commissioned to report on improvements, and he was responsible for the remodelling of the SW range as a ball-room wing in 1775-7 (for George Herbert, second Earl of Powis). In 1801, the castle was inherited by Edward, second Lord Clive, and the Powis Earldom was re-created for him (for the third time) in 1804. As heir to the Clive fortune, he was able to commission Robert Smirke to carry out improvements to the castle, between 1820 and 1830. Thereafter, the final major alterations to the castle were carried out by G.F. Bodley, c1904, for the Fourth Earl. On his death in 1952, the property was given to the National Trust.
The Medieval Castle: By c1300, the castle comprised an outer bailey to the W, with curtain walls to the N and W at least, and an inner ward built around a courtyard, with twin gate towers to its W. It had previously been assumed that the SE angle tower constituted the earliest surviving part of the medieval castle, but recent research has shown that the curved section of the S wall of the inner ward pre-dates it and may represent the remains of a late C12 shell keep, which was subsequently substantially rebuilt when the buildings were extended northward in c1300; the gate towers are probably contemporary with this c1300 phase, together with the N curtain wall of the outer bailey, with the lower storey of the accommodation on its inner face (the present ball-room range). The N range of the inner ward has not yet been investigated in detail, but it is thought to represent the hall range of the C13 castle: the walls appear to be substantially of medieval masonry. The E gate tower may have been added in the C15, when the castle was owned by the Grey Family.
The C16-C17: Major remodelling of the castle followed its acquisition by Edward Herbert in 1587, though largely within the confines of the medieval structure: he added the long gallery on the N and W sides of the inner courtyard, and perhaps the portal on its E side; there are fragments of C16 decoration in other rooms, and documentary evidence for much more, suggesting that the establishment of the interior layout of rooms en filade may date from this time. Most of the present pattern of fenestration was established in the C16-C17 period, although the window details have been several times renewed. While the internal layout of rooms as it survives on the first floor may be late C16, most of their detail and decoration is no earlier than the later C17, with much work of c1660. It now seems likely that a major Baroque remodelling was initiated after the Restoration, and as part of this, new entrances were designed: new pavilions flanking the W entrance were added in 1668, and the main portal at the E (with a corresponding portal at the W, subsequently re-sited), also appears to be late C17. The Baroque programme used local craftsmen at first, but under the direction of William Winde from the 1670's, it attained a greater sophistication of design and planning. The insertion of the grand staircase between 1674 and 1685 (attributed to Winde) entailed further alteration to the internal layout and it may be that the inner walls of the NW drum tower were cut-down at this time to accommodate it.
The C18: Documentary sources record work carried out at Powis between 1748 and 1754, by William Burke, but it is not known what this entailed. However, it is known that further refenestration took place during the C18 (largely probably using existing openings); illustrations of the castle record some sash windows, and in 1856, the Third Earl remembered the draughty 'French sashes' which were replaced by Smirke. Thomas Farnolls Pritchard was responsible for the remodelling of the ball-room range, which had been detached from the castle following a fire in 1725.
Smirke's Restoration: Some sources suggest that Smirke was working at Powis between 1815 and 1818: but others suggest 1820-1830, and Paul Sandby Munn's water-colours of the castle in 1816 clearly pre-date Smirke's involvement. He refenestrated the castle, re-instating stone mullioned and transomed windows, and also raised the E gate tower by an additional storey to enhance its picturesque status. He also added new embattling, and made some alterations to the internal layout, including enclosing the loggia underneath the long gallery.
Bodley's Restoration: G.F.Bodley made minor alterations to the external appearance of the castle (for example removing the curved angle turret to the N of the E gate tower and replacing it with a canted oriel, and renewing windows, largely in earlier openings), and considerable alterations to the interior, including changes to the layout of rooms (notably the creation of the dining room from two smaller rooms), and an extensive programme of redecoration.