a turkish fable: the converted cat

The Cat, having put on the cowl and become a monk, sent word to the mice and said :
"It is an abominable thing to shed blood. As for me, I will shed no more, for I am become religious."
Then the mice replied :
"Although we saw in you the whole Order of St. Anthony, or of our holy Father St. Mark, we could have no confidence in your hypocrisy."
The Cat covered herself with a dust rag, and smeared herself with flour. The mice approached her, saying:
"Wretch, we see through your dust rag!"
Then she pretended to be dead, and lay in the path of the mice, who approached her and said :
''Miserable cheat, although your skin be made into a purse, we could not believe that you had given up your habitual knavery."
This fable shows that when you have once found out a person of dishonest, treacherous, and evil character, you should not trust him, even if he tries to do right, for he cannot change his nature.

-- I personally feel that's too harsh a judgement, but it's an entertaining find. From Turkish Literature; comprising fables, belles-lettres and sacred traditions (New York: The Colonial Press, 1901), pp.20-21.