
Seller description (ebay) for this item:
Maggie Howe Los Castillo Mexico Turquoise and Green Enamel On Copper Tray 5 1/4 inch at the widest point, One small manufacturing defect on the back see pic #3 but does detract from overall quality of this great piece .American born artist Maggie Howe was the first person that introduced enameling into Mexico .Maggie Howe worked with Miguel Angel Pineda 1958 to 1960 is a Mexican artist who has worked, fostered and cultivated enameling in his country.There is no reference to whether or not Maggie actually introduced enameling to Mexico (tho I am skeptical). Very little is written on Ms. Howe and I have seen very few pieces by her. There is no doubt however that she did work or collaborate with Miguel Pineda - her pieces including her very signature screams Miguel Pineda as do her pieces.


So on a quick google search I evidently found the source for the above reference that Ms. Howe 'introduced' enameling to Mexico (still skeptical)
website: glass-on-metal.com/pastart/miguel_pineda.htm
more text from the source glass on metal:
Miguel Angel Pineda is a Mexican artist who has worked, fostered and cultivated enameling in his country. His earliest contact with this art was when he met the first person that introduced enameling into Mexico - the American born artist Maggie Howe - with whom he studied between 1958 and 1960. Later on, he devoted himself to experimenting on his own, learning different techniques and developing a very keen interest towards pre-Hispanic art. To this day, he has created a vast selection of pieces on this subject, as well as jewelry, trays, vases and ashtrays. His techniques include cloisonne, Limoges, wet packing and particularly champleve. He has devoted himself entirely to enameling since 1966.