Peter Sonna built the first phase of this building in 1888 on the corner of 9th and Main. The lower floor was used as the site for the Peter Sonna Hardware Company, and the upper floor was an opera house. Architect James King built the second and third phases in 1891 and 1895. These phases were extensions for the hardware store, and looked very different from the first phase. If you were to look at old pictures of the building (old pictures hang in the lobby, we photographed these pics for the site) up to the 1970s, you would see the discrepancy of window levels, styles, and the roofline. The whole building was remodeled in 1976 to look uniform.
After Peter Sonna died, the lower floor was divided into four parts. The left most part was an entry stairwell to the upper floor, which is no longer accessible from the other three parts. The other three were converted into stores and restaurants, which have changed over the years as demonstrated by historical pictures, and are still occupied today. The upper floor was converted from an opera house into immense office space, which is what it is used for today.
The architectural style of the Sonna Building is modified Romanesque. If you look at the side of the building today, you can see the characteristic uneven rough brickwork. This detail is prominent on the inside walls of the building as well. The windows also indicate the style to be Richardsonian Romanesque. Some of the other interesting parts of the building are the cast iron columns that used to be there, large plate glass windows and a still visible crested iron roof.