Complex sentence: To the Cambodians, these lands were known as Kampuchea Krom and traditionally under the control of the Khmer Empire until the era of Chey Chettha II when they came under the control of the Nguyễn lords.
Split into simpler sentences: To the Cambodians, these lands were known as Kampuchea Krom and traditionally under the control of the Khmer Empire. From the era of Chey Chettha II onwards, they came under the control of the Nguyễn lords.