The story
A medieval Spanish royal name, of probably Gothic origin, and debated meaning, possibly 𐌲𐌰𐌹𐌻𐌾𐌰𐌽 (gailjan) + *𐍅𐌴𐍂𐌴𐌹 (*wērei), thus "joyful sincerity". It became famous outside Spain after its appearance in Mozart's Don Giovanni (1787). The place name Elvira is a contraction of the older Illiberi, new city.
Etymology from Wiktionary, CC BY-SA 4.0.