Complex sentence: The seax has a lasting symbolic impact in the English counties of Essex and Middlesex, both of which feature three seaxes in their ceremonial emblem, and whose names, along with those of Sussex and Wessex contain a remnant of the word "Saxon".
Split into simpler sentences: The seax has a lasting symbolic impact in the English counties of Essex and Middlesex, both of which feature three seaxes in their ceremonial emblem. Their names, along with those of Sussex and Wessex contain a remnant of the word "Saxon".