Looks to me to be your classic 2 bits. A cut in half Spanish cob or 4 reales. Value back in the day of a quarter. They would colitis the coins to make change when small change was scarce
Actually, your coin is a English short cross penny of either Henry II, Richard I, or John. Your coin shows the moneyer's (the person who produced the money) name, but since it has been cut in half the mint name is not visible. It was cut in half to make change. The halfpenny and farthing (fourthing) of British predecimal currency at first meant just that, a penny cut into halves and fourths respectively. I will try o work on the moneyer's name.
The front reads HENRICVS REX (Henry king) and a cross, and the back reads (moneyer name) ON (mint name) and a cross. On yours you can read some of Henricus and the letter O.
