is it a roman sword or a celtic one?

[Urselius]

The Sudanese 'kaskara' and Tuareg 'takouba', are straight bladed swords, but the blades do not have a diamond cross-section, the blades taper, they don't have parallel edges, and are usually multiply fullered. The Masai 'seme' does have a somewhat similar tip to the one shown, but semes are very short swords and also don't have a diamond cross-section.