The staircase of the church was Carl Ludwig Engel’s last design. Before Engel’s death, the Main Guard Post of Helsinki was located in front of the church, by the edge of Senate Square. Main Guard Post was demolished in the 1840s, and the current steps leading up to the church terrace were built in its place. Also, other additions deviating from the original plan were made to the church after Engel’s death, including terrace pavilions on both sides of the steps.
Carl Ludwig Engel (1778-1840) was a prominent German architect who made significant contributions to the field of architecture, particularly in Finland. He is best known for his work in designing and shaping the architectural landscape of Helsinki, the capital city of Finland. Engel's architectural style was neoclassical, and his designs reflected the ideals of symmetry, proportion, and classical aesthetics.
Engel's most famous works include the Helsinki Cathedral (Helsingin tuomiokirkko), which is an iconic symbol of the city, and the Senate Square (Senaatintori), a neoclassical architectural ensemble that is a UNESCO World Heritage Site. He also played a crucial role in planning the city of Helsinki, helping to transform it into a modern, European capital during the early 19th century.