The Genoese established their trading factories along the Abkhazian coastline in the 14th century, but they functioned for a short time. The area was relatively spared from the Mongol and Timur's invasions, which terminated Georgia's "golden age". As a result, the kingdom of Georgia fragmentized into several independent or semi-independent entities by the late 15th century. The Principality of Abkhazia was one of them, and was formed around 1463. The Principality of Abkhazia, whereas it acted as an independent state, was officially a vassal of the Kingdom of Imereti, following a treaty signed in 1490 splitting Georgia into three nations. The Abkhazian princes engaged in incessant conflicts with the Mingrelian potentates, their nominal suzerains, and the borders of both principalities fluctuated in the course of these wars. In the following decades, the Abkhazian nobles finally prevailed and expanded their possessions up to the Inguri River, which is today's southern boundary of the region. Several medieval historians like Vakhushti and a few modern ones claimed that the Kelasuri Wall was built by prince Levan II Dadiani of Mingrelia as a protection against Abkhaz.