Museum opening of the year: The Liechtenstein Museum, Vienna: the restoration by Prince and Princess Hans-Adam II von und zu Liechtenstein of the family's Garden Palace in Vienna as a setting for works of art from the Liechtenstein collection has provided Austria with a major new museum. Andrew Wilton visited the palace, which opened to the public in March

Apollo, Dec, 2004 by Andrew Wilton

Until recently, the Garden Palace of the Princes of Liechtenstein in Rossau, a suburb of Vienna, housed the Museum of Modern Art. It was an incongruous association: One of the great baroque palaces of Europe was home to a collection representing the aesthetic of a very different age, an aesthetic that seemed almost to deny the aristocratic splendour of the building.

Since 2000, that has changed. Prince Hans-Adam II von und zu Liechtenstein and his wife, Princess Marie, with their director of collections, Johann Kraftner, and a team of craftsmen, restorers and scholars, have brought the palace back to glittering life; its garden is a vista of shrubs, flowers and sculpture; its semi-circular forecourt houses a pleasant cafe, its saloons and staircases are reverberant with the colours of newly-restored frescoes and ceiling paintings.

The house was first planned by Fischer von Erlach for Prince Johann Adam Andreas, who built a slew of fine palaces across central Europe in the late seventeenth century. He chose Fischer because of his training under Bernini in Rome, but in the event that was not Italian enough for the Prince. He turned instead to Domenico Egidio Rossi and then to Domenico Martinelli, who finished the job in 1702. The house was adorned with numerous sculptures and its spacious interiors decorated by two Italian painters, Andrea Pozzo and Marcantonio Franceschini, together with the Viennese Johann Michael Rottmayr. (Those interested in Rottmayr can at the moment ascend the dome of Fischer yon Erlach's great Karlskirche in Vienna to survey both the restoration of Rottmayr's frescoes of the apotheosis of S Carlo Borromeo and the panorama of modern Vienna from the lantern.)

Johann Adam Andreas was not only a compulsive builder: he also collected painting and sculpture with avidity. From the sixteenth century the Liechtensteins had been amassing art of a high order, and in the early nineteenth century the palace at Rossau became a permanent home to some of the finest pieces, to which the public was given access. Only with World War II did this state of affairs end, when the collection was removed to Vaduz.

No less than the great Kunsthistorisches Museum on Vienna's Ringstrasse, this is a truly international gallery. The first object to seize your attention as you enter the radiantly lit Sail Terrena is Prince Joseph Wenzel von Liechtenstein's sumptuous rococo carriage, all gilt scrollwork, crimson velvet and painted amoretti, made in Paris in 1738 by Nicolas Pineau. Beyond are the handsome neo-classical library brought here in 1912 from the family's town house in the Herrengasse, and a sequence of rooms filled with eighteenth- and nineteenth-century paintings and sculptures. Here are two highly informative views of the Garden Palace by Bellotto and a number of portraits and small pictures representing the Liechtenstems' taste in the nineteenth century for German masters such as Rudolf von Alt and Friedrich Georg Waldmuller. These rooms are presided over by Canova's exquisite seated figure of Leopoldina Esterhazy, a version of which occupies the tempietto erected as her mausoleum by the lake in the English Garden at the Esterhazy's palace in Eisenstadt, not far away.

Ascend either of the two grand staircases that flank the entrance hall, under ceilings (now in restauro) by Rottmayr, and you reach the overpoweringly grand Herculessaal, with its frescoes by Pozzo illustrating Hercules' labours. From this open the galleries devoted to renaissance and baroque art. In Gallery IV are Italian renaissance paintings, among them Piero di Cosimo's delicious Madonna and Child with St John in a Landscape (c. 1505-10) and Catena's Christ carrying the Cross from the 1520s. Gallery V is a room of portraits, including a sensitive head of a man by Barthelmy d'Eyck, of 1456; a swagger whole-length by Hans Mielich of Ladislaus von Fraunberg with an alert leopard whose spotted coat challenges the ornately embroidered doublet of his master; and a deeply introspective male portrait that is called, and looks plausible as, Raphael. In this room too are specimens of the pietra dura work beloved of Prince Karl I, the founding father of the Liechtenstein collections. Spectacular pieces of furniture of many periods are scattered throughout the galleries.

Gallery VI is devoted to the Italian baroque, with pictures by Cortona, Solimena and Batoni alongside sculptures by Giambologna, Susini and Massimiliano Soldani Benzi, a late-baroque master much collected by Prince Johann Adam Andreas. There are more fine works by Benzi in Gallery VII, which also holds two sculptural masterpieces by Adriaen de Vries: The Man of Sorrows (1610) and St Sebastian (1613-15). But the chief glory of this room is the great series of eight tapestry designs by Rubens (executed with Van Dyck's assistance) depicting the life of the Roman hero Decius Mus, who is presented as a type of ancient heroic virtue. Each is massively framed by an ornate gilt rococo cartouche carved by Giovanni Giuliani in 1706. Here also is Rubens's Assumption of the Virgin, which once hung in the church of the Liechtensteins in Valatice, Moravia.