Although glass making was know in the Ancient world centuries before the Roman Empire, glass blowing started around 40 BCE.
This is the famous Ennion piece from the first-century A.D.(just over 9 inches tall). It is thought to be a wine jug and has the Greek inscription ENNIWN E OIEI (Ennion made it) :
Here is the related video:
Here is another related video:
Interesting stuff,
guy