At the beginning of the 15th century, Tatar tribes inhabiting the right bank of the Dnieper were driven away by the Grand Duchy of Lithuania. However, by the mid-15th century, the Nogai (who lived north of the Sea of Azov) and the Crimean Khanate invaded these lands. The Grand Duchy of Lithuania and the Crimean Khanate agreed to a border along the Dnieper, and farther east along the Samara River, i.e. through what is today the city of Dnipro. It was in this time that there appeared a new force, the Cossacks, armed freemen not subject to any feudal lord who were to soon dominate the region. They later became known as Zaporozhian Cossacks, from Zaporizhzhia, the lands south of Naddniprianshchyna, which translates as "the Land Beyond the Weirs "). This was a period of raids and fighting causing considerable devastation and depopulation in that area; the area became known as the 'Wilderness'.