Complex sentence: He surmised the possible date of ethnogenesis as 800 AD, he hypothesizes that the Sama-Bajau originated from a proto-Sama-Bajau people inhabiting Zamboanga who practiced both fishing and slash-and-burn farming lifestyles.
Split into simpler sentences: He surmised the possible date of ethnogenesis as 800 AD. He hypothesizes that the Sama-Bajau originated from a proto-Sama-Bajau people inhabiting the Zamboanga Peninsula who practiced both fishing and slash-and-burn farming lifestyles.