Or is it “I” for “Iuno?”
In either case, the deity whom I am referring to is the goddess of women, marriage, childbirth, matronly values, femininity, and the Roman people (back before Christianity gained power). She is the sister and wife of Iuppiter, the daughter of Saturnus, the mother of Vulcanus and Mars, and, along with Iuppiter and Minerva, held a position in the powerful Capitoline Triad.
Like the other Roman deities, Iuno has many epithets. Three of her most well-known epithets are Moneta, Regina, and Sospita. In her role as Moneta, Iuno is called “The Warner” and is a protector of finances: she had a temple dedicated on the Capitoline hill where sacred geese were kept, because they had warned the people of an impending attack. In her role as Regina she is the Queen – the wife of Iuppiter and the Queen of the Gods. As Iuno Sospita she is the Savior, the defender and protector of her followers.
Interestingly enough, she is often mentioned in vows and offerings together with Hercules, as both are seen as the protectors of newborns.
The Kalends, the first day of every month, are sacred to Iuno. She is said to bring the first day of the month into existence with the help of Ianus, and is at this time invoked as Iuno Covella. Her sacred animals are the peacock and the goat (she is often depicted as dressed in a goatskin cloak), and her sacred foods are the fig and the pomegranate.
In Virgil’s Aeneid, Iuno was very much an antagonist towards the titular hero, Aeneas. She did not like him, mainly for the reason that his descendants would found Rome, which would destroy Carthage, her favorite city. She spent much of the epic as a scheming, bitchy character who did everything in her power to make life difficult for Aeneas and his band of Trojans. Like with all literary portrayals of the gods, this is not how she should actually be seen.
The tutelary deity for women takes its name from Iuno as well. While men have a sort of guardian deity known as the genius, women have a iuno. And it is not just mortal women who have this iuno: goddesses also do, if ancient inscriptions are any help.