Well-preserved remains of medieval buildings and roads have been discovered under the floor of the gymnasium of the Cathedral School of Åbo in Turku, Finland. When the gym’s floor was removed during renovations. Workers found the remains of two houses, vaults, staircases and a paved road from the 14th century.

It is not an unexpected find. The oldest city in Finland, Turku was founded in the 13th century, and while the medieval center of the city around the cathedral had to be rebuilt after it was levelled by fire in 1827, excavations in the 1990s unearthed the foundations of 13th and 14th-century stone and brick houses, and numerous artifacts. At that time Turku was the site of the bishopric and Turku Cathedral, consecrated in 1300, which is just down the street from the school. Aboa Vetus next door to the school has integrated the medieval remains under its floors into only archaeological museum in Finland.

Even though it is houses in a 19th century from the post-fire reconstruction, the school itself has been in existence since the 13th century and given its location in the heart of the medieval monastery district, it is unsurprising that medieval remains have been found on school property before, including in a dig of the schoolyard just last year, a dig that it still ongoing.

“What was surprising is how well preserved these are. Traces of these were noticed by the archeologist Juhani Rinne when the gym was built at the beginning of the 1900s, but now the picture has come into focus,” says the leader of the dig team, Kari Uotila. […]

Hundreds of cubic metres of fill have been hauled out of the dig site, revealing the walled ruins and vaulted cellars. Now down a metre and a half into the soil, the team has reach floor level in parts of dig.

According to Kari Uotila, some of the cellar vaults collapsed after the great fire of 1827.

“These are 2.5 metre high vaults that were broken during the reconstruction of the city. Right now, we’ve uncovered about a dozen different vault structures, as well as staircases and hallways belonging to two buildings.”

Excavations will continue for another month. The archaeological team is hoping to reach the floor level of the houses. The really thorny problem is what to do after that. The whole point of tearing up the gym floor was to build a new one with fresh supports. Those support pilings as currently planned cannot be constructed without largely destroying the ruins. Uotila is hoping the remains will be left in place and that the shoring supports issue will be sorted out so that the remains can still become integrated into the building as a display.

Installing a transparent floor with magic carpet supports that would make the medieval city visible as the kinds runs around and dunk basketballs would be awesome, no question, but may not be possible or be the best solution for the long-term preservation of the structures. Local architect Benito Casagrande thinks they should go another way altogether.

Casagrande says that there are construction alternatives that can be used to straighten the school structure and build a floor that would not require pilings. The floor could be raised and a false ceiling in the gym removed, leaving plenty of space and air for student activities.

“This is a terrible significant find. I think all of these well preserved ruins are unbelievable treasures which should be put on public display for people to experience. Gradually, we are understanding what a large and handsome city Turku was in the 14th century,” argues Casagrande.