ah, I thought you were referring to the Matrix in the way the architect sees it "The emergence of the anomoly (The One)"

 

Since there is no background on the "Perfect" Matrix other than it failure due to it's unrealistic features we cannot be sure if The Mero was created before or after. It is most plausible according to the amount of power and info he has, he has been around for several instances (Anamoly cycles), probably even to the beginning of the Anamoly (current Matrix).