However, Sonck's style would soon go through a dramatic change, in the direction of Art Nouveau and National Romanticism that was moving through Europe at the end of the 19th century.

A prominent figure in Finland's search for architectural identity – at a period when Finland was a Grand Duchy under the control of Russia and Finnish politicians, intellectuals and artists were defining a distinct national identity – Sonck played a leading role in the development of National Romanticism, along with such other architects as Herman Gesellius, Armas Lindgren, and Eliel Saarinen.

A fantastic sketch accompanying Sonck's competition entry gives an indication of the imagery he was aiming for, inspired by his travels in Germany.

Historian Pekka Korvenmaa makes the point that leading theme was the creation of the atmosphere of medieval urban environments – and Sonck later designed a similar proposal in 1904 to rearrange the immediate surroundings of St.Michael's Church in Helsinki, with numerous "fantastic" spired buildings.

The final plan (1916) under the direction of Jung, made the scheme more uniform, while the architecture is seen as typical of the Nordic Classicism style.