Iron arrowhead or Pilum end piece. A square shaped tapering to a point with a slight bend in it. A shaft or iron leaves the point and end abruptly.
This could have been an arrow head designed for penetrating Chain mail armor as the shape indicates. The size and the thickness of the shaft however make me think that it could be the end piece to a Roman Legionary Pilum, which would have had a similar type of point. The Pilum was the weapon of the Legionary next to his Gladius, and essentially was a thin shaft with a pointed end. A wooden shaft was also then attached to the iron shaft creating a long spear length weapon. Sometime a weighted piece was added between the iron shaft and the wood. The theory was that the Pilum could be thrown, impacting the enemy and bending. This meant that the Pilum could not then be thrown back at the Legions. It was not until the later 3rd- 4th Century that these were no longer used.
It is also possible that this "arrow" was also used as a balista(crossbow type device) bolt/tip. This would most likely have been larger than a regular arrow and used to penetrate numerous enemy soldiers.
It also is possible that it belongs to a later period.
**any help in finding sources for this item would be appreciated, as I have none**
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**Note on background. A Fresco from the ancient Roman City of Pompeii. The interior walls of a wealthy Roman's Estate 79AD. Picture taken July 2005.