It is said of the person who moves with ease in a place that is not his own. Sometimes it has a pejorative meaning, because it is an intruder whose attitude is impertinent, arrogant or excessive.
An old saying goes, “Something goes from Peter to Peter,” meaning that there are differences even among those who look alike. And others, also forgotten: “Old is Peter for a goat,” “Peter is well in Rome, even if he does not eat.” All these sayings, and many others, indicate that Peter is the name given to any individual, to personalize phrases, sayings or sayings. More specifically, Peter seems to represent the owner or master of a house, as if it were a very ancient relation of the Christian words according to which St. Peter was the cornerstone or the first stone of the House of God. Some authors, however, have tried to identify this Pedro with Pedro I of Aragon (11th and 12th centuries) alluding to an old saying: “To enter like Pedro by Huesca”, alluding to the little resistance that had this king in the of that city.