Cervantes from certain solecisms of language pronounces him to be an Aragonese, and Pellicer, an Aragonese himself, supports this view and believes him, moreover, to have been an ecclesiastic, a Dominican probably.
Any merit Avellaneda has is reflected from Cervantes, and he is too dull to reflect much.

"Dull and dirty" will always be, I imagine, the verdict of the vast majority of unprejudiced readers.

He is, at best, a poor plagiarist; all he can do is to follow slavishly the lead given him by Cervantes; his only humour lies in making Don Quixote take inns for castles and fancy himself some legendary or historical personage, and Sancho mistake words, invert proverbs, and display his gluttony; all through he shows a proclivity to coarseness and dirt, and he has contrived to introduce two tales filthier than anything by the sixteenth century novellieri and without their sprightliness.
But whatever Avellaneda and his book may be, we must not forget the debt we owe them.

But for them, there can be no doubt, "Don Quixote" would have come to us a mere torso instead of a complete work.

Even if Cervantes had finished the volume he had in hand, most assuredly he would have left off with a promise of a Third Part, giving the further adventures of Don Quixote and humours of Sancho Panza as shepherds.