 Complete the following phrase:  In the third lunar month of 1287, the Yuan dynasty launched their third invasion of Đại Việt. This time, unlike the second invasion, commander-in-chief Prince Hưng Đạo Trần Quốc Tuấn assured the Emperor that Đại Việts army could easily break the Yuan military campaign. After occupying and looting the capital, Toghan decided to retreat with the forward troops. This invasion was indeed ended one year later by a disastrous defeat of the Yuan navy at the 