The medieval past of Tver, the capital of a large principality and a rival to Moscow, is full of secrets in many respects. The time of the first fortress construction, the location of first wooden churches and the design of the first stone cathedral were not known for a long time. The way to success was paved by systematic research conducted by the expedition of the Institute of Archaeology together with the Tver Research Historical-Archaeological and Restoration Center during excavations in the Tver Kremlin (2012–2014). The tip of the Kremlin promontory at the confluence of the Volga River and the Tmaka River, the central part of the fortress where the Savior Transfiguration Cathedral had been built and the area east of the cathedral occupied by a former non-classical secondary school were explored.
The earliest city wall of the hook-based design (hooks were installed at the end of the stacked logs to keep them firmly in place and prevent them from shifting) (a radiocarbon date puts the wall construction not later than the middle of the 12th century) was unearthed for the first time at the confluence of the Volga and the Tmaka. Residential quarters with densely packed houses, pavements and wooden fences abutted on the city oak wall; the dendrodates of the two logged blocks (not the earliest) are 1149 and 1150. Several more structures were identified underneath; the lower occupation layer does not contain any glass bracelets (there is an abundance of such bracelets in the overlying layers; they were popular among city female residents in 1160–1170).
The numerous finds are typical for an Rus city. Of special interest is a wooden board completely covered with a carved design in the Scandinavian Romanesque style (the radiocarbon date of the board sample (KIA-50975): cal AD 1010–1160; University Laboratory, Kiel, Germany).
A charcoal bed left by fire, which burned down the wall, overlies the oak wall remains. After 1238 (dendrochronology date) the wall was replaced by a complex fortification construction made of pine semi-block houses. Therefore, fortifications existed in the promontory area of the Tver Kremlin as early as the pre-Mongol period not later than the second half of the 12th century, while the population started settling in the promontory not later than the second half (the first half?) of the 12th century.
The examination of the remains of the Savior Transfiguration Cathedral, which is the first large cathedral built in North East Rus after the Mongol devastation, is of paramount importance for history of Russian culture. The remains of the building dating to 1285–1290 and the new cathedral that subsequently replaced the old one (1689–1696; it was blown to pieces in 1935) were explored in the area exceeding 1,400 m2. Despite the fact that the 12th century cathedral was demolished twice, the archaeologists were lucky to identify the sub-footing base of the foundation pits as well as white stonework in the southern part and even unearth a white stone porch along the axis of the south entrance, mentioned in the description of Grand Prince Mikhail’s resignation (1395).
The layout of the cathedral is traced by partially intact sub-footing bases of the foundation pits, which were not reinforced with pile fields. It was a three-naved, three-apsed and four-pillared cathedral with three narthexes. The overall width, including the south and north galleries, was 21–22 m. The cathedral is extremely large in plan and is close to a square. However the bay below the dome and the central apse measure 4.5–4.7 m; this is a common feature of churches built in the 12th–13th centuries, which are not the largest, though noteworthy. Polygonal apses extending to the east is a typological characteristic of the plan, the central apse extends from the inside for around 12 m, which is approximately half of the cathedral length; the side apses are narrower and are placed close to the central apse.
White stone debris, including debris with carved ornament, and plaster pieces with fragments of fresco painting (including a fragment of the elaborately painted face and hands) prove that the cathedral was built of white stone; its layout was typical for the early 13th century, the cathedral was decorated with stone carving of the Vladimir-Suzdal type; introducing a new architectural and artistic style that had its roots in the early Moscow construction, the carvers, however, maintained pre-Mongol traditions.
Remains of a necropolis, with most graves (184 out of 192) made before the construction of the stone cathedral and associated with the wooden church of Saint Cosmas and Damians, survived at the site where the 12th and the 17th century cathedrals were built. All early burials were made in wooden coffins or tree-trunk sarcophagi, sometimes overlaid by a layer of birch bark. Fifty-two burials contained offerings such as temporal rings, bronze buttons, glass bead necklaces, rings, crosses worn next to the skin and a bronze belt buckle. Six burials yielded remains of headwear, 11 burials contained remains of collars with a birch bark used as a support material; the birch bark was covered with cloth with gold embroidery; and a unique set consisting of headdress and a collar with sewn-on silver plaques, some with glass inserts.
The occupation layer and the pits of the second half of the 12th–20th centuries were examined in the sections adjoining the cathedral foundation. A ground floor of the pre-Mongol period (12th century) survived in the south-eastern part of the excavation pit. Several structures with ground floors sunk into natural soil dating to the 15th – second half of the 16th centuries (one of the structures is very large) were explored near the east boundary of the excavation pit. The finds related to this period include a treasure hoard of hammered silver coins shaped as fish scales from the Time of Troubles buried in a small money-box near the cathedral apses.
During the restoration of the Tver Museum building (a former non-classical secondary school) east of the apses of the Savior Transfiguration Cathedral the excavations revealed dwelling quarters, channels for palisades, pits of the medieval period made in natural soil. The occupation layer underlying natural soil is noted for absence of glass bracelets (which are found in the overlying deposits). Of interest is a treasure hoard consisting of Rus silver jewelry (triple bead temporal rings, star- and ray-shaped colts (temporal pendants, which hung from the headwear on ribbons or chains), ornamental pendants, beads, plaque medallions, a wide bracelet made of two leaves). The items were wrapped in a cloth and put into a pot placed with its bottom up into a pit. The jewelry pieces are made in granulation and filigree techniques, sometimes with niello and engraving. The items may be dated indicatively to the end of the 12th – first half of the 13th centuries, and are possibly linked to the devastation and looting of Tver by Batu Khan in 1238.