Around what years did surnames in England become hereditary?

Question:

Around what years did surnames in England become hereditary?

I know surnames in England were around since probably 900 AD, but around which years did average English people start passing a surname on to the next generation?

Best Answer - Chosen by Asker: What you get free is guesses. Since Ireland started family surnames around 1100 ad, my totally wild scientific guess is it was around the same time.