Montefortino helmet, 1st Century B. C. to 1st Century A. D.
For over a hundred years those classical bronze helmets with a projecting peak at the rear to protect the wearer's neck and with°a rounded conical- or hemispherical bowl have been known to scholars by the descriptive term 'Jockey 'Cap', helmets, items which they so closely resemble.

Source: A wood near Millingen, Prov. Gelderland