When were glasses invented?

Throughout the ages, people have used different tools similar to glasses to see. For example, Seneca the Younger used a globe of water, and Emperor Nero of Rome used an emerald. The first wearable gasses, however...well, no one knows who REALLY created them. They just have guesses. Here they are:

Someone in China

Some one in the Middle East

Someone in Italy

Salvino D Armate.

No one is sure, and I think there are other opinions, too. Hope this helps!