As in the modern day, glassware in antiquity was considered an art form, with the best pieces being valued higher than wares made from precious metals. Glass bottles, such as this interesting example, were used as containers for ointments, powders, balms, and other expensive toiletry liquids, especially perfumes: the small mouth of the bottle is ideal for slow, careful pouring, while glass was preferred for holding liquids, due to its non-porous, non-absorbent nature. Glass vessels are found frequently at Hellenistic and Roman sites, especially in cemeteries, and the liquids that filled them would have been gathered from all corners of the expansive Roman Empire. Thanks to the invention of glass blowing it became possible to create moulds in order to mass-produce popular designs. Unusual shapes, like this example, experienced great popularity.
To learn more about Roman glass, visit our relevant post: How It Was Made: Roman Glass.