Complex sentence: The British intervention in Johor-Riau-Lingga-Pahang is to further develop their dominance in the Strait of Malacca after controlling Dutch Malacca under Treaty of The Hague earlier in 1795.
Split into simpler sentences: The British intervention in Johor-Riau-Lingga-Pahang is to further strengthen their dominance in the Strait of Malacca. They have earlier gained Malacca from the Dutch under Treaty of The Hague earlier in 1795.