Of blackened iron, with two-piece skull with low turned comb, pointed peak stamped with maker's mark 'R' for Francis Rolenson, with turned edge, and three-bar face-guard joined at the bottom to form a scroll, bluntly-pointed neck-guard of three simulated lames with turned border, and dome-headed rivets, with hanging pendant ear flaps (replacements). 

R

Francis Rolenson, who is known only from his mark. He is probably the same as Francis Rawlinson to whom Thomas Dobson was apprenticed from 1626-34, and Thomas Leeson from 1627-35. 

Tom Richardson (2004) The London Armourers of the 17th Century, Henry Ling Limited, Dorset Press, UK.