[1] A member of the gentry, Leyson was born in Neath, Glamorgan circa 1549 and roughly 20 miles from St. Donat's Castle.
Although the exact date is unknown, in the mid-1580s, Leyson settled into a medical practice in Bath, where he eventually died.
Leyson wrote a Latin poem celebrating St Donat's Castle, which was translated into English by his friend John David Rhys.
The construction at St. Donat's is a major theme of the poem, in which Leyson complements Stradling's contributions as patron.
Stradling was so impressed by Leyson's poem that he commissioned Rhys to complete the Welsh translation, which is over 100 lines long.