When the Timeline and the Historical Account Don't Fit

I'm currently working on the Coningsby family, a project that takes me back to the late 1100s and early 1200s. The subject of frustration is one John Coningsby. John reportedly met his fate at the Battle of Chesterfield in Derbyshire, as one of the Barons opposing King John. Simple, right?

Oh not so, dear reader! The Barons opposing King John fought the First Barons War [1215-1217]. King John died in 1216. The Battle of Chesterfield, Derbyshire took place during the Second Barons War in 1266.

The Coningby pedigrees and other sources vary on the inclusion of dates. What is clearly available is that Baron Coningsby was alive "anno 2 King John," the 2nd year of the reign of King John. John ascended to the throne following the death of King Richard I in 1199. Year two would have been 1200 or 1201. That establishes that John Coningsby was alive in 1200/01.

King John died in 1216, during the First Barons War. Therefore, if Coningsby fought against King John and was killed in battle, then it was during that military conflict.

The problem is that the Battle of Chesterfield took place 50 years later. Those sources that give a birth for Baron Coningsby, place the event about 1162. He would have been in his 50s in 1216 and over 100 in 1266.

The single source noting John Coningsby's death is Richard Clutterbuck's History & Antiquities of the County of Hertford  published in1815. On page 445, Clutterbuck states that John
was, for his rebellion against Kinge John, disinherited, and after, in a battle which the Barons and disinherited gentlemen gave ths Kinge att Chesterfield, in Darbyshire, slayne in the field; and so the Barony, which had contynned in that name from the Saxons till then, vvas then finished, as by auncient recorde
doth appeare. Was Clutterbuck in error as to John Coningsby's place of demise? Did he confuse 1266 for 1216? I have not found a battle at Chesterfield taking place in 1216. Castles at Rochester, Dover and Winchester were under siege in 1216. The Battle of Lincoln took place in 1217. Did John dies during one of these sieges? The Coningsby family was of Lincolnshire. Was John defending his home shire.

Without supporting or conflicting documentation, it would seem that Mr. Clutterbuck had the circumstances correct, but the geography in error.