Alexander m. Ancient Greek ἀλέξω 'I defend' + Ancient Greek ἀνδρός, gen. of Ancient Greek ἀνήρ 'man'.
The name of a 2nd C pope and saint, a 3rd C Roman emperor, five 3rd C saints, three 4th C saints, a 5th C saint, a 10th C Byzantine emperor, an 11th C pope, two 12th C popes, a 12th C king of Scotland, a 13th C pope, two 13th C kings of Scotland, a 13th C prince of Novgorod and Kiev and saint, a 15th C antipope, a 15th C saint, two 15th C kings of Georgia, a 15th c prince of Wallachia, a 15th C grand duke of Luthania, a 15th-16th C pope, and a 16th C prince of Moldavia. Wycliffite Bible (1395): Alisaundir
The popularity of this name was reinforced by various medieval Romances about Alexander the Great, one of the nine worthies. The English diminutives Saunder, Saundir, and Sawndir are witnessed in 1379 in the relational bynames Saundersoñ (WRYPT1 p. 307), Saundirson (WRYPT1 p. 16), and Sawndirsoñ (WRYPT1 p. 132).