Complex sentence: Its name was changed to Charles City County in 1643, and it is considered one the five original shires in Virginia which are still extant in essentially the same political entity (county) as they were originally formed in 1634.
Split into simpler sentences: Its name was changed to Charles City County in 1643. It is one the five original shires in Virginia which are extant in essentially the same political entity (county) as they were originally formed in 1634.