The Cathedral Basilica of Saint Stephen is a basilica in Székesfehérvár, Hungary. It was built in the late 1010s by Saint Stephen I, the first King of Hungary. The basilica was an impressive building, but neither exceptionally large nor a technical miracle. At that time, important archiepiscopal cathedrals like those of Mainz and of Cologne were once and a half as large. The four Papal Basilicas of Rome were between twice and four times as large. Last not least, Hagia Sophia in Constantinople was three times as large and of much more an ambitious construction.