Việt settlers arrived in the sparsely populated area known as "Water Chenla", which was the lower Mekong Delta portion of the former Khmer Empire. Between the mid-17th century to mid-18th century, as the former Khmer Empire was weakened by internal strife and Siamese invasions, the Nguyễn Lords used various means, political marriage, diplomatic pressure, political and military favors, to gain the area around present-day Saigon and the Mekong Delta. The Nguyễn army at times also clashed with the Siamese army to establish influence over the former Khmer Empire.