The previous arms of the University of Barcelona are those established under the Moyano Act (1857), which set up the university districts. They show the arms of the four Catalan provinces and the Balearic Islands (the university district of Barcelona included all these territories), as well as a female head corresponding to Medusa, one of the three Gorgons. Medusa appears on the shield of Athena, the goddess of wisdom and intelligence, and is one of her attributes.
When the University of Barcelona was officially opened in 1822 (although still coexisting with the one in Cervera), the figure of Minerva (the Roman equivalent of Athena) appeared on the institution's emblem, accompanied by a Latin motto saying "Wisdom is the mother of all good arts". After the Moyano Act, the Sun was placed on the arms, with the text Perfundet omnia luce, which can be translated as "Wisdom impregnates everything with light". This entire group, made up of the arms of the Catalan provinces and Balearic Islands, the Sun and the motto, was sometimes topped off with a Royal crown (sometimes the crown of the County of Barcelona or the Principality of Catalonia), or surrounded by a laurel wreath.
It seems that the motto Perfundet omnia luce was incorporated by the UB in the period when work on the Paranymph Hall was being completed, which is why it appears on the Paranymph Hall canopy and the upper landing tapestry on the main staircase. Despite this, some bibliographical sources maintain that the motto, with the word libertas included (Libertas perfundet omnia luce), was a creation of Fernando de Castro (1814-1874), a liberal priest with Krausist tendencies who was Rector of the Central University of Madrid between 1868 and 1870.
During the Second Republic, in the period when the University of Barcelona enjoyed the Statute of Autonomy, Rector Pere Bosch Gimpera wanted to recover the word libertas, but it was never included in the official University arms. It appeared only on a commemorative medal commissioned from the sculptor Clarà.
During the Franco dictatorship, the arms of the university district were replaced by those of Cervera, with the image of the Immaculate Conception, and it was not until 1970 that the motto Perfundet omnia luce was restored, together with the arms of the university district. At the start of the academic year 1987-1988, there was a renewed desire to include the word libertas in the motto.
Since then, the motto of the University of Barcelona has been Libertas perfundet omnia luce. This is an adaptation of a passage by the Roman philosopher and poet Lucretius, in which the word sol (sun) has been replaced by libertas (liberty).