Powis Castle. A taste of 13th-century grandeur in Wales

WALES is overrun with castles. To visit this small country without seeing at least one of its hundreds of them is unthinkable. They symbolize its history, its beauty, and even its sadness. In her 1985 book, ``The Matter of Wales,'' Jan Morris jocosely characterizes some of them adjectivally.

Caerphilly Castle, for instance, is ``astonishing.''

Chepstow Castle is ``brutal.''

Dinefwr Castle: ``haunting.''

Cardiff: ``exhilarating.'' Others are ``jolly,'' ``domesticated,'' ``silly,'' or ``insensitive.''

Powis Castle, just south of the market town of Welshpool, is in the rural county of Powys, mid-Wales. Jan Morris calls it ``much the most comfortable.'' Although it began life as a Welsh fortress, she writes, it has been ``for 350 years . . . a luxurious country residence.''

In fact, this red stone castle, its cliff-like walls rising high above steep, terraced gardens, has been continuously inhabited since the last decades of the 13th century. The presumably wooden fortification, which had previously stood on the same narrow outcrop, had been destroyed in one of the repeated skirmishes between the Welsh princes in this border area. Its owner, for good or ill, had formed an alliance with the nearby enemy, England.

Thanks to this alliance, the stone castle was subsequently built. It has been altered and enriched over the centuries since, but still retains externally the air of a 13th-century fastness. Its owner, Gruffyd ap Gwenwynwyn, was given back his possessions by English King Edward I, when Edward at last managed to subdue Wales.

Comfort in an ancient castle must be rather a relative term, but the visitor to Powis today feels a grandeur warmed and softened by centuries of family living. Even now, with Britain's National Trust running Powis, making many of its attractions accessible to tourists, the current (sixth) Earl of Powis still lives here. The trust specializes in this kind of arrangement for its properties, and often achieves a remarkable balance between their private and public character as a result.

The trust's administrator at Powis, Major Neville Williams, showed us around. He led us up the grand 17th-century staircase, into the library, the blue drawing room, the ``gateway room,'' the oak drawing room. He commented fluently on works of art, furniture, Mortlake tapestries, ceiling paneling, murals, family portraits, Indian relics. These last are from the collection of Lord Clive of India, whose son married a Powis heiress in 1784 and later became Earl of Powis.

Two portraits indicated by our guide were of Clive's daughters. They were by the delightful 18th-century portraitist George Romney. Joshua Reynolds's fine skills are also represented, by a portrait of Lady Henrietta Herbert. This Countess of Powis, living until 1830, was a descendant of the Sir Edward Herbert who had purchased the castle during the reign of the first Queen Elizabeth in 1587. Dreamlike, visionary painting

The castle's most remarkable picture is also of a Herbert: Protected in a glass case, this small, sparkling gem of a painting, dreamlike and visionary, is Isaac Oliver's 17th-century miniature on vellum of Lord Herbert of Cherbury, brother of George Herbert, the metaphysical poet.

In the blue drawing room Major Williams drew particular attention to a pair of 18th-century black lacquer commodes -- English, with Japanese panels. Dating from the 1760s, they are attributed to Pierre Langlois.

Looking through one of the many windows (which from the outside break up and humanize the defensive fa,cades of the castle), he told us that some of the walls are 13 feet thick. Their red gritstone was quarried here. Nearby landmarks include the River Severn; Britain's tallest tree; and Offa's Dyke, the 8th-century entrenchment marking the boundary between Anglo-Saxon and Welsh territory. To the northeast are the Breidden Hills.

Some of the upstairs windows look over the remarkable terraced gardens sloping southwards from the house. The white figures of shepherds and shepherdesses on the balustrade above the orangery are, he told us, actually made of lead. Thay had recently been painted white to look as they would have originally: a cheap substitute for marble. The rustic elegance of these rare pieces is, in fact, a charming feature of what basically are formal gardens.

These gardens vie with the house for visitor appeal. Thought to have been laid out in the late 17th century, they withstood -- apparently through neglect rather than a deliberate effort -- all the dangers of ``improvement'' common in British country-house gardens through the 18th century, often at the hands of ``Capability'' Brown. He, given the chance, would have informalized them. Instead they have kept a distinct period flavor and are reminiscent of Italian Renaissance terraced gardens. Rich Elizabethan plasterwork

Their powerful regularity and geometry have, all the same, been allowed to mellow over the years. Flowers climb, hang, and festoon the terraces, clothing the severity of the stonework. The enormous yew hedges are possibly the most unusual development of all. They billow up almost like dark clouds, strange amorphous masses of green. Over the centuries they have achieved a scale commensurate with the castle itself. It is hardly surprising that W. Robinson, the vigorous exponent in the 1880s of ``the wild garden,'' said few gardens gave him more pleasure than Powis.

But Powis as a whole is not unused to praise. And two of its finest rooms were still waiting for us: first, the ``long gallery.'' Long galleries were much more than passages. They were for weatherproof exercise and display of pictures, tapestries, furniture, and sculpture. Mark Girouard has called Powis's, formed at the end of the 16th century by Sir Edward Herbert, ``one of the most evocative of Elizabethan long galleries.'' He relishes its ``wonderful, rich Elizabethan plasterwork.''

Major Williams then took us into the oddest room in the castle, the state bedroom. This opulent, though not enormous, 17th-century room intrigues architectural historians. Richly gilded balusters cross the room. A portion of the balusters swings open like a garden gate to give access to the tapestry-surrounded bed. Crowns and the initials CR indicate its royal function. Experts seem to agree that the king in question was not, as traditionally thought, Charles I, but his son, Charles II. That the Herberts were ardent Royalists is well-known. Their allegiance had provoked an invasion of the castle during the civil war by Cromwell's parliamentary troops and resulted in temporary exile for the Herberts. But at the second Charles's restoration in 1660, they were reinstated. Practical information

Powis Castle and Garden are open to the public Wednesday through Sunday, March 29-April 13, and in May, June, and September, Wednesday-Sunday, 1 to 6 p.m. In July and August, the garden is open daily from 12 noon to 6 p.m., and the castle, Tuesday-Sunday, 1 to 6 p.m.