Hatfield

[TennesseeTim]

Dear RootsChat Community.
My name is Tim Hatfield.  I live in Tennessee, USA.
I came across your website while searching for Hatfield genealogy, and I write with the hope that you will possibly answer a question for me regarding my family name.
I have done a great deal of genealogy research on my family name in the States.  My interest has broadened, and now relates to the history of how the name was originally adopted.
Please allow me to state a few things that I believe to be true, followed by my question.  If any of my facts are incorrect, I will greatly appreciate being corrected.
* The name Hatfield evolved from the name Haethfeld, which in the Saxon language meant Field of Heather.
* The Saxon King Edgar gave the monks of Ely land to build their monastery in the area known then as Haethfeld in the year 970.
* The monks brought with them 54 families, which I assume to be of Saxon heritage, to settle the area.
* The Hatfield House contains the original foundation of that monastery, and the town of Hatfield grew nearby.
* Another village called Hatfield lies east of York, north of Leeds, in Yorkshire.  That area, north of Doncaster, was known in ancient times as Meicen, and was a Celtic-Welsh stronghold against the Saxon invaders.
My question is:  Did medieval families begin adopting their family names from the places they lived before or after the Norman Conquest?  If before, it would mean that early families who lived in the Haethfeld area near Hertfordshire, including many present day Hatfields, are probably of Saxon ancestry?  Or, were family place names already in use at the time that King Edgar gave the monks the land in Haethfeld, meaning that many present day Hatfields are probably of Celtic ancestry?  If you're a British Hatfield, do you consider yourself more of Saxon or Celtic ancestry?
I surmised that the former was true until I discovered that another, probably older town of Hatfield, exists in Yorkshire.  Now I believe the latter is probably true.
Any help you will provide will be greatly appreciated.
If you have a recommendation of where I might search to find additional answers, that will also be appreciated.
Thanks so much,
Tim Hatfield.

[TennesseeTim]

Hi Folks.
Obviously, I made my first question too lengthy.
More simply put, I am wondering which English town or village of Hatfield is the oldest?  The place name Hatfield is mentioned in the Anglo-Saxon Chronicle in the year 680, but was the area named for a family, or did families from the area adopt the place as a name?  Which came first, the chicken or the egg?
And what is the opinion of the British Hatfields?  If you have traced your family as far back as they can be followed, where does it begin, in Celtic or in Saxon ancestry, or are there other factors I have failed to consider?
Any assistance is greatly appreciated.
Thank you,
Tim Hatfield.