Complex sentence: It is reported that Edward the Elder died in the ancient parish of Farndon in AD 924, shortly after quelling a revolt of an alliance of Mercians and Welshmen which involved him successfully taking Chester from them, and then re-garrisoning it shortly before his death.
Split into simpler sentences: It is reported that Edward the Elder died in the ancient parish of Farndon in AD 924, shortly after quelling a revolt of an alliance of Mercians and Welshmen. This involved Edward successfully taking Chester from the occupying Mercians and Welshmen, and then re-garrisoning it, and this happened shortly before his death.