The city became famous for the Battle of Saule, which took place in 1236 near Siauliai. It was in historical chronicles detailing the battle between the armies of Lithuania and the Order of the Crusaders that Siauliai was mentioned for the first time.
Šiauliai was a city plagued by fire in 1652, 1661 and 1701. In 1872 a fire has burned down a large part of the city. In 1915 a fire started by German occupants destroyed some 65 % of the houses in Siauliai. Approximately 85 % of the buildings were razed during World War II. Siauliai has since been rebuilt as a modern city. The only thing left of the old city is the Church of the Sts. Peter and Paul which rises up where the centre of Siauliai once was. The church was built in 1634 and although it has been reconstructed a number of times, both the interior and the exterior remain in their original Renaissance form. The tower, which is 70 m tall, is of particular interest. The 750th anniversary of the Battle of Saule was commemorated by the erection of a 21 metre high sundial, capped by an archer in gilded bronze, on the lakeshore beside the town centre.
Near the town, on the left bank of the Kulpe River sits the famous Hill of Crosses. After the rebellions during the 1800s, people from near and far began to put crosses on the hill till our days.