Complex sentence: Lomboko was scattered across several small islands at the mouth of the Gallinas river, near Sulima on the Gallinas coast that was controlled by Spanish slave merchants, within the British colony, and modern-day country of Sierra Leone.
Split into simpler sentences: Lomboko was scattered across several small islands at the mouth of the Gallinas river, near Sulima on the Gallinas coast. The area was controlled by Spanish slave merchants, within the then-British colony and modern-day country of Sierra Leone.