About Agostina Calleja
Based on historical evidence, the Maltese version of the surname is likely not related to the Spanish version. The first written appearance of the Calleja surname in Malta predates both Aragonese rule (1283–1412) and Aragonese/Castilian rule (1412–1530) of the Maltese island—appearing in 1271 AD with the spelling Calleya and Caleya.
On May 22, 1271, Bertrando de Real, the magister of Malta, was instructed to keep a note of the names and surnames of those who transported the falcons to the royal court from Malta, Martinus Calleya was a witness and Leo Caleya is among those included in the list. Of note, the persons on the 1271 document belonged to the wealthy class and did not include any serfs or peasants, nor any surnames of Arabic derivation. One theory is that the surname Callea or Calleya in Malta is of late Greek or Byzantine formation—Commendatore Fr. Abela, the father of Maltese history, believed the surname to be of Greek origin.
In the fifteenth century there was a village in Malta called Calleja, situated near Mosta—it seems linguistically and geographically connected with il-Qlejgħa, in the same geographic area. Wied il-Qlejgħa (more popularly known as Chadwick Lakes) means the Valley of the Small Castle.
Sources: 1 http://www.familytreedna.com/public/calleja/default.aspx 2 Melita Historica New Series. 12(1999)4(333-344), p.333, The Origin of the ‘Maltese’ Surnames, Prof. Godfrey Wettinger 3 Melita Historica New Series. 12(1999)4(333-344), p.333, The Origin of the ‘Maltese’ Surnames, Prof. Godfrey Wettinger 4 Melita Historica New Series. 12(1999)4(333-344), p.333, The Origin of the ‘Maltese’ Surnames, Prof. Godfrey Wettinger 5 Journal of Maltese Studies. 5(1968)(25-48) [p.25] The Distribution of Surnames in Malta in 1419 and the 1480s G. Wettinger
The only way to know for sure if the Maltese and Spanish surnames are similar is for a Spanish male Calleja to have his DNA testes (a $99 cost). The Y-DNA Haplogroup for the Maltese Calleja is fairly rare.