Duke Rudolph IV of Habsburg, in 1359, laid the cornerstone of the Gothic nave with its two aisles. The South Tower (Südturm), 448 feet high, was completed in 1433 (the Viennese have given it the nickname Steffl, which also denotes the whole cathedral). After 1511, building in the Gothic style ceased; the unfinished North Tower (Nordturm), 224 feet high, was capped with a makeshift Renaissance spire in 1579.
During the 18th century, the cathedral was decorated with Baroque altarpieces - the panel of the main altar shows the stoning of its namesake St. Stephen, the first martyr of Christendom. forward
The view from the South Tower is restricted due to renovations.