Porossya defensive line is a system of fortifications in the basin of the river Rossi, which consisted of fortresses and Snake (tree-earth) ramparts. Built in the XI-XIII centuries in order to protect the southern border of Russ from the attacks of nomads. Passed along the left bank of the river.
The creation of the defensive line began in the 30s of the XI century. Among the first fortresses built in Porossya was the annalistic Korsun. In the XI century this fortress ended the Porossya defensive line in the lower current of the river. At the end of the XI-XII centuries four fortresses were built below Korsun. Their remains are preserved near the modern villages of Nabutiv, Sakhnivka, Mezhyrich and Kononcha. The defense system was also strengthened due to the “rear” fortifications on the left tributaries of the Ros. The remains of one of them are preserved in the village of Pishky on the river Nekhvoroshch.
The construction of new fortifications is also connected with the process of settling about and staying of Turkic nomadic tribes in Porossya. Their union, which originated in the middle of the twelfth century, was called black hoods. Lightly armed cavalry of black hoods protected the southern border of Russ from the Polovtsians.
At the end of the XII century Polovtsy during the campaigns in Russ preferred the route that passed through the lower current of Ros. Due to the growing Polovtsian threat, the latest Middle Shaft in Porossya was built, which ran along the left bank of the river below and above Korsun.
Scientists have identified several territorial groups of settlements in Porossya, including Korsun. In the XII-XIII centuries. the fourth part of the settlements of this group consisted of fortresses: khutir Polovetskiy, Mykolayivka, Stebliv, Korsun, Pishky, Nabutiv, and Sakhnivka. The average distance between them was 6.6 km.
In the second half of the XIII century. as a result of the Mongol campaigns, the Porossya defensive line lost its significance.