It was made by Giulio Monteverde (the english Entry is a bit poor.... Try the german one if you can...)
Strange thing though: There are quite opposite opinons about the Angel: Some Boffin in the German Wikipedia is convinced (i wonder why?) that she is not the usual grieving angel attached to the deceased but in contrary she is lacking interest for the one she's supposed to guard and that she's distant, closed and unfathomable.
I happen to have a copy of a book (printed in the 20s of the last century) and i'll quote what it says about that particular Angel:
....The Angel, who guards the urn, is admired for the perfect moulding of the arms, neck and head, the deep and soft expression of grief which appears on his features....
So much about being distant and not atttached.
In my opinion these discussions doesn't matter at all. The point is: It is a marvellous and unbelievably beautiful Sculpture.