Complex sentence: After the demise of most of the royal family ("togoʻiti"), the Gambier Islands steadily fell under colonial influence, it having already been a French protectorate since 1871 under Regent Arone.
Split into simpler sentences: After the demise of most of the royal family ("togoʻiti"), the Gambier Islands steadily fell under colonial influence. It already been a French protectorate since 1871 under Regent Arone.