During the 12th century in Italy a Signore would not only refer to a man but the head of the town. This person would be in charge of everything that went on in the specific town.

The Signore was an inherited title. The only other way of gaining the said title was to invade the town and take over.

Si*gnor" (?), Si*gno"re (?), n. [It. See Seignior.]

Sir; Mr; -- a title of address or respect among the Italians. Before a noun the form is Signor.

© Webster 1913.