Cup and saucer by Franz Rumwolf, parcel gilt, Vienna, Diana’s head.
The question: was there a glass or china insert in there? Unlike tea cup/glass cup holders, it seems no insert would fit in here; it would fall out when drinking. Besides, it was probably meant for Milchkaffee (Café au lait) and not for tea, therefore not too hot drink; easy to drink out of silver. Have seen (mostly French) cups, all being without glass or china insert.