Things are always a little fuzzy when going back to 304 AD but, going on faith and whatever records the Romans left behind, Diocletian ended the lives of a nine year old boy and his thirteen year old brother on religious grounds. Justus (the elder) and Pastor are believed to be the subject of this fountain's naming.
This is the second oldest fountain in Barcelona. In 1367 this fountain, in the Placa de Sant Just, sprung to life. The original three heads would have been the sources for the water. Today there are 2 spigots between the 3 heads. Up above is a single figure of what looks to be a young boy; suppositions are that this is a depiction of Saint Just(us). But, after 100 years, who can really say with any certainty?
In 1831, it had a minor face-lift/reconstruction. It still looks like it is original.
Still, it is a medieval treasure, so simple and free of formality and pomp. Amazing how the people of Barcelona can set up tables, chairs, and cafes around treasures like this that are 1,700+ years old. Seems like they should be under protective glass.