possessives - Break a Cup of His Own

For this sentence:

He broke a cup of his own.

Does it mean

1. that he broke a cup of unknown ownership after someone else had broken a cup, also of unknown ownership, or


2. that, after breaking a someone else's cup, he then broke a cup that belonged to himself?

Answer

Context.

For the former case, I could say: they were arguing in the resteraunt. The first man grew so angry that he broke a cup and the other, in retaliation, broke a cup of his own.

For the latter: When he grew angry, he broke a cup of his own [because that was what he had on hand].

I prefer the former usage only because it would usually be "his own cup" rather than "a cup of his own", but perhaps this is just due to my inability to come up with a good example. Both ate reasonable interpretations.