Complex sentence: The names of the Celtic Iron Age tribes in Britain were recorded by Roman and Greek historians and geographers, especially Ptolemy, although information from the distribution of Celtic coins has also shed light on the extents of the territories of the various groups that occupied the island.
Split into simpler sentences: The names of the Celtic Iron Age tribes in Britain were recorded by Roman and Greek historians and geographers, especially Ptolemy. Information from the distribution of Celtic coins has also shed light on the extents of the territories of the various groups that occupied the island.