Complex sentence: Lan Xang was the first to voice support for the Chinese domination, even sending troops to fight alongside the Chinese against Lê Lợi's Lam Sơn Uprising, but after the defeat of China in 1427 the Laotians feared the vengeance of Vietnam.
Split into simpler sentences: Lan Xang was the first to voice support for the Chinese domination, even sending troops to fight alongside the Chinese against Lê Lợi's Lam Sơn Uprising. However, after the defeat of China in 1427, the Laotians feared the vengeance of Vietnam.