Most likely the name is derived from place names:
The Oxford Dictionary of British Place names, lists the name as possibly being derived
from the Somerset village of Bleadon "N.Som. Bleodun 956. Bledone 1086 (DB) 'Variegated hill'. OE "bleo
+ dun". This dictionary also gives the explanation for Bladon as "Oxon. Blade 1086 (DB), a Pre-English river-name
of uncertain origin and meaning, an old name of the River Evenlode."
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or ...
From "1246 - 1st September Wudestock
Alan de Bladen, Simon de Hesfield, John de Bladen and Walter Stille, free men of county
Oxford, Have mainperned before the king ... " Source: PRO. Title: Close Roll 30 Henry III.
From "1298 - 20th January Ghent
Mandate to make letters of pardon for Hugh de Bladene in the county of Oxford, indicted
of robberies ... "Source: PRO. Title: Chancery warrants 26 Edward I 15/1426.
The entry in "A Dictionary of English Surnames" (rev'd ed.) Reaney & Wilson lists
the following which I think is the earliest written reference in documentation the authors could find: "Hugh de Bladene 1279
RH(O) from Bladon (O) or Blaydon (Du)".
I think it is safe to assume that the Dictionary's Hugh in 1279 and my reference in
1298 are one and the same person. From this I therefore have interpretted it as being a surname derived from a place
name.
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Reference to Blaydon, in Tyne & Wear (formerly in County Durham). - The village
of Blaydon in Northumberland is supposed to have originally been Black Aydon, shortened over the years to Bl.Aydon, then Blaydon,
so unlikely to be relevant.
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Another possibility: is the name Bladon derived from the Latin - word meaning
"side of a hill"
