Syringa vulgaris ?
Agree with aswhad - lilac.
google rejuvenation pruning of flowering shrubs.. review such.. then meet us in the shrub forum.. if you want to learn about taming this beast ...
it will become enormous.. if you dont wack it down thru the years ... using the method above ...
Thanks for the ID and information. The purple is starting to come out. We inherited this bush and it is already huge. I looked into the rejuvenation pruning and that seems to be a possibility.