WHERE DID THE WORD JACKASS COME FROM?

Found on the Internet, don't know who wrote it.

How did the word jackass come to describe someone behaving in a
negative or idiotic manner?

First we have to tell you how jackass came to describe what we today
call a donkey. Ass is a very old word, of even much older roots. In
late Old English it was assa, thought to have come from one of the
Celtic languages (Old Irish has asal). Many other Indo-European
languages had versions of the word which derived from Latin asinus,
but the record seems to indicate that the Celtic version(s) lent
themselves not only to Old English, but to Teutonic and Slavonic as
well. From this etymologists speculate that the Celtic form has as
its ultimate roots a Sumerian or Semitic word, which might explain
also where the Greek form onos (source of English onager) came from.
Hebrew has the word athon "ass".

Jack, used to identify the male form of a species, goes back to at
least the late 16th or early 17th century. In the case of the ass,
Jenny was used to refer to mares. There was a feminine form of ass
in Old English, assen (formed like the feminine form of fox, vixen),
but Jack and Jenny replaced the need for a feminine form.

Jackass used to describe a "fool" comes from the age-old association
of clumsiness and unintelligence with asses (that's what happens when
you've been domesticated for millenia!); this goes back at least to
the ancient Greeks and was perpetuated in the Bible. The purely
metaphorical use, calling a man an ass, arose in the 17th century.

Also, relatives of ass (and Irish asal) may be found in the German
ezel and Dutch esel. It is from this latter word that we derive
easel, the wooden ass which carries an artist's canvas.