In the modern era, they rank with Cleveland, the Giants (50's), Green Bay (60's), Miami (early 70's), Pittsburgh (mid to late 70's), Dallas (70's), the Raiders (70's & 80), Washington (80's- early 90's), San Francisco (80's and early 90's), and Dallas (90's) again as teams which arguably are all time dynasties.
I hate it when people call the patriots a dynasty. To me in order to be a dynasty you have to at least two championships back to back. They patriots have yet to repeat.