 Complete the following phrase:  Lasting for several centuries, the kingdom fell to the Mongol invasions in the 13th century, but managed to re-assert sovereignty by the 1340s. The following decades were marked by the Black Death, as well as numerous invasions under the leadership of Timur, who devastated the countrys economy, population, and urban centers. The Kingdoms geopolitical situation further worsened after the fall of the Byzantine and then Empire of Trebizond. As a result of these processes, by the end of the 15th century Georgia turned into a fractured entity. Renewed 