In 1882, when the Romanesque castle of Montcada in the old town of Vic was demolished, the remains of a Roman temple appeared among the ruins. This was the ancient Roman temple of Ausa which had been preserved in excellent condition. The building dates from the 2nd century, after the Roman conquest of Hispania. The reconstruction lasted for 77 years (1883-1959), but it is currently one of only two Roman temples throughout Spain to have been preserved practically complete.

The temple, built on a podium, consists of a cella (small chamber) and an atrium with 8 columns. Two of the walls of the cella were found almost intact. A capital, a section of the shaft of the column and the original fragments of the pediment were found amongst the rubble which allowed the exterior of the monument to be reconstructed.

The castle which occupied the temple area was built in 897 by Guifré el Pilós (Wilfred the Hairy) and, from the 11th century, was the property and residence of the Montcada family who reused the four walls of the temple to construct the castle’s central courtyard. Afterwards, the building was used as a residence of the veguer (feudal administrator), headquarters of the Royal Curia, the city’s granary and, finally, a prison and quarry. By the 19th century, it had lost its fortified appearance completely and had been converted into a rather forbidding mansion. Still preserved today are part of the vaults and walls of the north and west sections of the castle.