Simplify the following text for a Grade 14 native English-speaking person.
Original: The island was administered jointly by the British Phosphate Commissioners and District Officers from the United Kingdom Colonial Office through the Straits Settlements , and later the Crown Colony of Singapore .
Simplified: The island was ruled jointly by the British Phosphate Commissioners and District Officers from the United Kingdom Colonial Office through the Straits Settlements , and later the Crown Colony of Singapore .