Honestly, I don't know. But Wikipedia says it was a ligature of two letters ("Ь" and "I"), which later changed their values: https://en.wikipedia.org/wiki/Yery

Honestly, I don't know. But Wikipedia says it was a ligature of two letters ("Ь" and "I"), which later changed their values: https://en.wikipedia.org/wiki/Yery#Origin https://en.wikipedia.org/wiki/Yery#Origin