Complex sentence: The Temenggong had originally moved to Singapore from Johor in 1811 with a group of Malays, and when Raffles arrived, there were an estimated 150 people governed by the Temenggong, mostly of them Malays, with around 30 Chinese.
Split into simpler sentences: The Temenggong had originally moved to Singapore from Johor in 1811 with a group of Malays. There were an estimated 150 people under the rule of the Temenggong, mostly of them Malays, with around 30 Chinese.