Baron Leybourne is in Baronies of England Alphabetically, Baronies of England Chronologically, Extinct Baronies of England.
Before 12th March 1310 William Leybourne 1st Baron Leybourne (age 68) was created 1st Baron Leybourne. It isn't clear by what means he was created a Baron. The Barony appears to have become extinct, abeyant, on the death of the 1st Baron.
On 12th March 1310 William Leybourne 1st Baron Leybourne (age 68) died at Criccieth Castle [Map]. Baron Leybourne extinct or abeyant. His son had predeceased him without issue.