Alexius is the Latinized form of the given name Alexios (, polytonic , "defender", cf. Alexander), especially common in the later Byzantine Empire.
The female form is Alexia () and its variants such as Alessia (the masculine form of which is Alessio) in Italian.
Rulers
Alexios I Komnenos (1048–1118), Byzantine emperor
Alexios II Komnenos (1167–1183), Byzantine emperor
Alexios III, Byzantine emperor
Alexios IV, Byzantine emperor
Alexios V Doukas, Byzantine emperor
Alexios I of Trebizond, Emperor of Trebizond
Alexios II of Trebizond, Emperor of Trebizond
Alexios III of Trebizond, Emperor of Trebizond
Alexios IV of Trebizond, Emperor of Trebizond
Alexios V of Trebizond, Emperor of Trebizond
Alexius Mikhailovich (1629–1676), Tsar of Russia
Alexius Petrovich (1690–1718), Russian tsarevich
Religious figures
Alexius, Metropolitan of Moscow (1354–1378)
Patriarch Alexius I of Constantinople (1025–1043)
Alexius (c. 1425–1488), Russian archpriest who converted to Judaism
Patriarch Alexius I of Moscow and All Russia (r. 1945–1970)
Patriarch Alexius II of Moscow and All Russia (r. 1990–2008)
Alexius of Nicaea, metropolitan bishop
Saint Alexius of Rome, fifth-century eastern saint
Alexius, a monk and saint of Kiev - see Abraham and Onesimus of Kiev
Other
Alexios Apokaukos, Byzantine statesman
Alexios Aspietes, Byzantine governor
Alexios Branas, Byzantine general
Alexios Halebian, American tennis player
Alexius Meinong, Austrian philosopher
Alexios Mosele (Caesar), Byzantine heir-apparent
Alexios Palaiologos (despot), Byzantine heir-apparent
Alexios Philanthropenos, Byzantine general
Alexios Raoul (protovestiarios), Byzantine general
Alexios Strategopoulos, Byzantine general
Alexios Xiphias, Byzantine Catepan of Italy
Alexios (Assassin's Creed), a fictional character in Assassin's Creed: Odyssey
