The Medieval Warm Period (MWP) was a period of higher temperatures, that was recorded particularly in northern Europe, during the mid-9th to mid-13th Centuries AD. It presents a difficulty for the AGW lobby, which tries (a) to dimiss it as a local anomaly (see You Can't Have it Both Ways) and (b) claim that the temperatures then were cooler than now. It was during the MWP that vinyards flourished in Britain (Lamb, H.H., 1966, The Changing Climate, Methuen, London.) and during which the Vikings settled Greenland. It was a period when Europe flourished economically and during which the great gothic cathedrals were built.
Was it Local?
Only if you consider (for example) Canada, New Zealand and South Africa to be "local" to Northern Europe.
Was it cooler than now?
Not according to a majority of both quantitative and qualitative studies.
It should be noted that there is increasing pressure from the AGW lobby to suppress "politically incorrect" findings such as those above.
For detailed scientific work on the MWP, see the Medieval Warm Period Project