Simplify the following text for a Grade 5 native English-speaking person.
Original: The Order was founded to commemorate the British amical protectorate over the Ionian Islands , which had come under British control in 1814 and had been granted its own constitution as the United States of the Ionian Islands in 1817 .
Simplified: The Islands had come under British control in 1814 . It was given its own constitution as the United States of the Ionian Islands in 1817 .