Royal Palace of Madrid audio guide,
five stops, free.

Look up at the middle of the roofline, where the facade rises into a block with a clock in it. That clock is Francesco Sabatini's, and built into it is a bell from the building that stood here before, the Alcázar of Madrid. Keep that bell in mind, because everything you are looking at is the answer to a fire.

Madrid grew up around this ridge. Between 860 and 880 the Umayyad emir of Córdoba, Muhammad the First, put a fortress on this ridge above the Manzanares, and the settlement around it was called Majrit. In 1561 Philip the Second made the Alcázar the official home of the kings of Spain and brought the court to Madrid. Then, on Christmas Eve 1734, it caught fire. It burned for three days. Paintings and furniture were thrown out of the windows, many of them broke in the fall, and more than five hundred paintings from the royal collection were lost. By the twenty-seventh of December only a few walls and one tower were still standing.

You will hear that Philip the Fifth's French courtiers started it on purpose, to get a palace like Versailles. Patrimonio Nacional, which runs this place, says plainly that it is a legend.

Philip sent for the most famous architect in Europe, Filippo Juvarra, who drew a palace four times the size of this one, with twenty-three courtyards and a facade 480 metres long. Juvarra died in January 1736, the plan was judged too expensive, and his pupil Giambattista Sacchetti was told to fit it onto the old Alcázar's cramped, sloping site. So he built upwards instead of outwards: six storeys where the ground is level, eight where it falls away behind the palace. And no wood. Every floor is a vault, with timber only in the doors and windows, so that this building could never burn the way the last one did. The first stone went in under the centre of this facade on the sixth of April 1738, and its inscription says that Philip the Fifth rebuilt the castle to face eternity.

Now the two statues either side of the clock: Ferdinand the Sixth and his queen, Barbara of Braganza. There were meant to be kings all along this roofline, back to the Visigoths, with Moctezuma and Atahualpa among them. Charles the Third, the first king actually to live here, from 1764, found it too much and had the statues taken down off the cornices. Before you go in, look at the stone itself: grey granite below and white limestone above, two colours doing the work that all those statues were supposed to do.

Look up first, then down, because the ceiling and the floor are the only two parts of this room that Charles the Third ever saw finished.

This was his Pieza de Vestir, his dressing room, and after the throne room the most important room in his apartment. It was not a private room. The king dressed here in front of the court, as kings did then, so the room had to be a performance in its own right. He gave it to Mattia Gasparini, a painter and decorator who had come with him from Naples in 1759, and Gasparini produced this: Italian rococo taken as far as it will go, fleshy leaves, flowers, birds and oriental figures, the century's craze for chinoiserie in every corner.

To make it, three workshops were set up. Cabinetmaking was run by a German, José Canops. Bronzes were under Antonio Vendetti. And the embroidery workshop was headed by María Luisa Bergonzini, Gasparini's wife, so one of the three workshops behind this room was run by a woman.

It took decades. When Charles the Third died in 1788, only the marble floor, laid by Domenico Galeotti and Nicola Rappa, and the stucco vault, by Gennaro di Matteo, were done. The whole programme took about fifty years. The embroidered hangings went up under Ferdinand the Seventh, and the chairs only arrived under Alfonso the Twelfth, in the late nineteenth century. More recently the silk on the walls wore out and was replaced, and the original embroidery was painstakingly sewn onto the new fabric.

Find the clock called El Pastor, the Shepherd, by the Swiss maker Jaquet-Droz, which Ferdinand the Sixth bought. On the hour a seated shepherd plays the flute while little figures in eighteenth-century dress dance. The bronze chandelier and the candelabra in the corners are from Ferdinand the Seventh's time, and the table in the middle came from the Vatican workshops, a present from Pope Pius the Ninth to Isabella the Second.

One more thing about the rooms you have just walked through. Charles the Third liked his walls covered from the ceiling down to the dado with paintings, swapped for tapestries in winter against the cold and damp of Castile. In the antechamber next door, where he dined and talked with his ministers, the summer hang included Velázquez's Las Meninas. It stayed on that wall until it left for the Prado for good.

If the palace has a point, this is it. It is the one room that has never changed its job since Sacchetti drew it in 1737. Stand back from the dais and look up before anything else.

The ceiling is Giambattista Tiepolo's, The Triumph of the Spanish Monarchy, one of the last works of his life. Follow its lower edge around the room: the figures sitting along the cornice are allegories of Spain's regions and possessions, each with its own attributes, and at the corners stucco figures lean right out of the painted frame, so that you cannot quite tell where the plaster stops and the paint begins.

Charles the Third handed the room to Felice Gazzola, whose team finished it in 1772, and it is Naples in Madrid. Charles had been king of Naples and Sicily until 1759, and the furniture was made there, designed by Giovanni Battista Natali and carved by Gennaro di Fiore: twelve consoles and twelve mirror frames, all different within one design. The mirror glass came from the Royal Glass Factory at La Granja, and flat plates of glass this big were a technical feat. The walls are Genoese velvet embroidered by Andrea Cotardi. The palace reads the whole arrangement as a code: the four parts of the world, the four seasons and the four cardinal virtues, everything a king needed to govern well.

Now the lions. Four of them, gilt bronze, each with a paw resting on a reddish stone ball. They are older than the palace. Velázquez ordered them in Italy on his second journey there, for the Hall of Mirrors in the old Alcázar, and they were cast in 1651 and 1652 by Matteo Bonuccelli. There were twelve. Seven are in the Prado, holding up tables, and one was badly damaged in the fire of 1734. Charles the Third set these four here on purpose, together with Jacques Jonghelinck's bronze Planets from the Alcázar, to say that the new Bourbon kings were the continuation of the old ones.

The two thrones on the dais look like the heart of the room, and they are among its youngest things: twentieth-century copies of Charles the Third's own throne chair, and the arms on the canopy behind them were embroidered in the 1990s. The original chair, with Charles's likeness on the back, is kept in the Crown Room, and every later throne was modelled on it.

This room also had a sadder duty. When a king died, his body was laid out here before it went to the pantheon at El Escorial. Charles the Fourth wanted to redecorate it, and a 1790 design by Sabatini and the French decorator Dugourc still exists, never carried out. So above you is what Charles the Third signed off on: Tiepolo overhead, Naples on the walls, and Velázquez's lions guarding an empty throne.