Thieves have stolen the antique gold medallion traditionally worn by the rector of Bologna University on ceremonial occasions.
Along with the rector's medallion and its gold chain, the thieves who broke open a safe in the university's administrative offices also took a medallion of the Academy of Science, another of the university seal, a 19th-century clock and a small amount of cash.
Police believe the theft took place when many of Bologna's inhabitants were away for the weekend, the university was closed and a nearby building site provided easy access to the administrative offices.
The thieves broke in through an emergency exit and used an oxyacetylene torch to cut open the safe. They also damaged a desk that once belonged to the 19th-century poet Giosu Carducci while trying to force open its drawers.
The rector's medallion - which has been worn by the head of Europe's oldest university since the early 19th century - is described as being of "inestimable value".
It is a unique piece that has never been bought or sold - a large piece of finely crafted gold with the heads of two popes who came from Bologna, Benedict XIV and Gregory XIII.
According to the police, the medallion would be extremely difficult to sell, raising the suspicion that the theft was commissioned by an unscrupulous collector.