If somehow you were involuntarily sent back in time...

[kenberman]

how would you prove to people that you were from the future?

Lets say you woke up tomorrow morning and found yourself in rural England, year 745AD. You're not a middle age historian, so you have no knowledge of the specific date/time of any event 'scheduled' to occur in the next 30 years.

You have nothing with you from the future, as even your clothes have somehow been transformed into typical clothes for 745AD in England.

How would you prove to people that you are from the future?

Could you 'invent' something? 'Discover' something?