The Duc du Berry and brothers Limbourg disagree with you (note the little guys on the table)...
(c. 1412)
...Certainly, by the time Van Eyck painted Arnolfini and His Bride (c. 1434) small domestic breeds were established and had themselves become an icon of fidelity (i.e., "Fido") such that they were common in wedding portraits...
In fact, they show up in a number of van Eyck's paintings...
