It is a statement with a few grains of truth.
There`s more than a grain of truth to that.
Stereotypes often have a grain of truth.
Our observations may contain a grain of truth for you to refer to.
Now again, what's interesting about this myth is that although it's basically a myth, there is a grain of truth to it.
However, perhaps one reason why this myth has survived is that there is a slight grain of truth to it.
But some scholars believed that behind the superhuman feats and divine miracles there must have been a grain of historical truth - a war that was really fought, and a place where it happened.