Highlight and list the consequences of the fortress campaigns to the east.

It is customary to call the crusades a set of military-religious campaigns of Christian Western European states, which were focused on overcoming the influence of Islamic Middle Eastern countries and pagan Slavs (the nationality was called the Lithuanians). The period of the Crusades dates back to the 11-15th centuries. The Eastern Crusades contributed to the decline of European feudalism, as a result of which the existing feudal foundations disintegrated. The event in question contributed to the extinction of the Byzantine Empire.