Fortifications of the Ust-Tersyuk fortified settlement of the Early Middle Ages

The article analyses early medieval structures of the outer fortification line in Ust-Tersyuk hillfort by the Iset River. The research is based on excavation finds made in 2010 and 2023. The fortified cape settlement is surrounded by a protection structure all around. Besides, it has two transverse structures that separate the cape and gullies and form two sites. One of the sites is pentagonal, the other one is octagonal. It is established that the structure lasted through at least four periods of functioning. These periods are separated from one another by intervals of desolation several centuries each. During these idle intervals the burial soil profiles started to form. Two early episodes are associated with the Bakalskaya culture and dated 300–400s. At that time the highest point was isolated all around with a stake wall as a temporary defence until earth works are over. Later the stake wall was disassembled and replaced with a low rampart, a 2 m wide berm and a moat across the slopes. In 500–800s the Bakalskaya culture people enhanced the defence with a mound and a 1.1 m wide wall over the mound. The wall cavity was filled with soil brought from the settlement site. Differences in the design of the wall on the cape (fence) and in the west flank (log framework) can be interpreted as different time of construction or troubled material delivery. The moat was relocated down the slope. The berm was enhanced to reach 5.5 m. In 1000s–1200s (Yudino culture) the moat around the hillfort was renovated. But the research is yet to establish the type of woks conducted on the ramparts. Every new episode of construction stands out with increasingly more efforts and attack marks. During the Bakalskaya culture the soil was meadow chernozem. The climate was warmer and humid due to close creeks. Later the climate got cooler and formed grey wood soil.