Simplify the following text for a Grade 13 native English-speaking person.
Original: The causes of the Bronze Age collapse - which extended throughout the eastern Mediterranean - remain obscure , although drought , famine and other stresses may be behind the widespread population movements of the time ; in any case , a number of important Canaanite cities were destroyed at the end of the Bronze Age ( although the process was spread out over more than a century ) , and Canaanite culture was gradually absorbed into that of the Philistines , Phoenicians and Israelites .
Simplified: The Canaanite city-state system broke down at the end of the Late Bronze period , and Canaanite culture was then gradually absorbed into that of the Philistines , Phoenicians and Israelites .