It’s a ‘one ardite’ (also ‘ardit’) coin from the Principality of Catalonia and was struck in Barcelona. It should be around 17mm diameter, but these coins are usually somewhat irregular.
These coins were struck from 1701-1711 and are from a very complicated period in Spanish history. Catalonia had done its best to maintain its status as an independent principality outside the control of the Spanish throne and under French protection.
At the beginning of the War of the Spanish Succession in 1701, the Bourbon Duke of Anjou claimed the throne of Spain as Philip V, and Catalonia initially supported that claim. Oppressive measures caused them to switch allegiance in 1705 when the Habsburg pretender to the Spanish throne, the Archduke Charles of Austria (as Charles III of Spain), landed in Barcelona. The Treaty of Utrecht (1713) put end to the war, but Catalonia carried on fighting until the fall of Barcelona in 1714 and occupation by the army of Philip V (who had originally been nominated to succeed Charles II of Spain, who died childless).
So, technically, this coin was issued under Charles III as pretender to the Spanish throne, but by an independent Catalonia who supported his claim. To further add to the confusion, many of the coins were overstruck on older coins of Philip IV which had previously circulated in Catalonia.