Janus
Janus (in Latin Janus, Ianus) in Roman mythology, is the god of doors, beginnings and endings. That is why the first month of the year (January) was consecrated to him and he was publicly invoked on the first day of January, the month that derived from his name (which in Spanish passed from the Latin Ianuarius to Janeiro and Janero and from there it derived to January). Janus is depicted with two faces, looking to both sides of his profile and has no equivalent in Greek mythology. The Janiculum, a hill located in Rome, owes its name to this god.
Among the many nicknames that the god receives, two are worth highlighting: Jano Patulsio (patulcius), which was used to invoke the face of the god that was located in front of the door for whom he wanted to go through it (to enter or exit). As a complement, the face that opposes it on the other side of the door is invoked as Jano Clusivio (clusivius) or Clusios. Both names declare the dual functionality of the god.
When the Sabines attempted to take the Capitol, Janus spouted boiling waters on the enemies, repelling them. For this reason he was invoked at the beginning of a war, and while it lasted, the doors of his temple always remained open, so that he would come to the aid of the city; when Rome was at peace, the gates were closed.
Like Prometheus, Janus is something of a culture hero, credited with the invention of money, navigation, and agriculture, among other things. According to the Romans, this god ensured good endings. In his treatise on the Fasti , Ovid characterizes Jano as the one who guards the gates of heaven in the company of the Hours.Jano is the father of Fontus, god of fountains, waterfalls and wells.