1 is correct. Things 'date back' for a length of time. It dates back 500 years. It dates back millennia. Things 'date back TO' a specific period or point in time. It dates back to the 15th century. It dates back to the 1940s. 'Dates from' is like 'dates back to' - it uses a point or specific period rather than a length. It dates from the 15th century. It dates from the 1940s. (Though I think dates back to sounds better.) To correct 2, you could say: It dates from several centuries AGO.