The settlement "Zamechek" in Zaslavl is a unique monument of archeology of the X century. On the top of the hill, which rises 24 m above the swampy floodplain of the blueberry river, a ring shaft was erected, on the crest of which there was a log defensive wall with combat platforms that allowed archers to conduct a circular fire. The approaches to the outer slopes of the fortress were blocked by a waterless moat and a stockade inclined towards the enemy, the entrance to the site was protected by a gate-tower. The correct geometric shape of the fortifications was optimal for the tactics of capture and defense known at that time. On the inner site of the settlement, log houses were located in one or two rows, in which the vigilantes with their families lived. The needs of the outpost were met by a trade and craft posad located on the bank of the Svisloch River.

The foundation and the name of the city are directly connected with the ancient legend about the rebellious Princess Rogneda (960?-1000), the daughter of the ruler of the Polotsk principality Rogvolod. The tale of Bygone Years, and after it the Laurentian Chronicle, tell in detail about these events. In 978, the Novgorod prince Vladimir Svyatoslavich (the future baptist of Kievan Rus) captured Polotsk, killed Rogvolod and his two sons, and took his daughter Rogneda by force to wife, and named her Gorislava. Even after the birth of her children, Rogneda did not forgive her husband for the murder of her father and brothers, and one night she made an attempt on Vladimir's life, which ended in failure. According to the customs of those times, she was threatened with death by her husband's hand. Rogneda was saved by his young son Izyaslav (979?-1001), who stood up to protect his mother with a sword. Struck by the bravery of his son, Vladimir replaced the death penalty with exile, and sent Rogneda along with Izyaslav away from Kiev, to the outskirts of the Polotsk lands. He settled in the upper reaches of the Svisloch, in a border fortress, which he ordered to be called Izyaslavl in honor of the brave prince. These events took place in 985, which is considered the date of the foundation of the city.

Today, the place of this fortification is known to scientists, residents of the city and visitors of the historical and cultural museum-reserve "Zaslavl" as the settlement "Zamechek".