The Theodosian church of St Sophia was destroyed on the first day of the great Nika rebellion of January 532. Its destruction provided Justinian with the pretext, at least, to rebuild it in a more durable and more magnificent form and presented his principal architects, Anthemius of Tralles and the elder Isidorus of Miletus, with an almost unprecedented opportunity. This opportunity they seized to the full. By a daring combination of structural forms never before attempted on such a scale, they created an interior whose superb spatial qualities still excite and amaze. A partial collapse in 558, little more than twenty years after the solemn dedication in December 537, showed that they had even been a little too daring and called for a partial reconstruction. But, after this had been completed by the younger Isidorus in 563, the rebuilt church acquired substantially its present form and remained for some 800 years the largest vaulted man-made structure in the world.