Five lines below John Heywood's mention of our famous grey feline, this phrase jumped out at us:
"No man ought to look a given horse in the mouth."
|Photo courtesy EPLEFPA Perpignan Roussillon via Creative Commons 3.0|
"Ah-hah!" we thought. "We just found the origin of another saying!" Boy, were we wrong.
But hey, we were only off by about, uhh...let's see...1,100 years, give or take.
Saint Jerome, circa 420 CE, wrote in his Commentary on the Epistle to the Ephesians,
"Noli...ut vulgare proverbium est, equi dentes inspicere donati"
"Do not, as the common proverb says, look at the teeth of a gift horse."
A Practical Guide to Lexicography, Piet van Sturkenberg, John Benjamins Publishing, 2003. Page 100.