Novgorod First Chronicle
The castle's age is disputed. Traditionally, the construction of the castle has been connected to Birger Jarl's Second Swedish Crusade, which would date the castle in the mid-13th century. However, there are no archeological finds from the castle that can be firmly dated to a period earlier than the 1320s. An earlier fortification from the early 1300s only some away in Hakoinen also contests Tavastia Castle's age, as only one castle ("Tauestahus") is listed in Tavastia in a royal document from 1308. Also, the Russian Novgorod First Chronicle only mentions one castle during their plundering of Tavastia in 1311, its description also matching with the castle in Hakoinen.