 Complete the following phrase:  After achieving actual or nominal dominion over much of Eurasia and successfully conquering China, Kublai pursued further expansion. His invasions of Burma and Sakhalin were costly, and his attempted invasions of Đại Việt northern Vietnam and Champa southern Vietnam ended in devastating defeat, but secured vassal statuses of those countries. The Mongol armies were repeatedly beaten in Đại Việt and were crushed at the 