High Quality Content by WIKIPEDIA articles! The Tegetthoff-class (sometimes erroneously named the Viribus Unitis-class) was the sole class of dreadnought battleship built for the Austro-Hungarian Navy. Four ships were built, SMS Viribus Unitis, SMS Tegetthoff, SMS Prinz Eugen and SMS Szent Istvan. Three of the four were laid down in Trieste, with Szent Istvan being built at Fiume, to incorporate both parts of the dual monarchy into the construction of the ships. The smaller size of the Fiume shipyards meant that Szent Istvan was built three years after her sisters, with slightly different characteristics.