If I understand correctly, until the 19th century, the word "peso" was the unofficial name of the Spanish colonial coin of 8 reales. But at some point, banknotes and coins began to appear with denominations in pesos written on them. Which banknote and which coin were the first?
From what I found on Numista:
3 and 5 pesos 1814 banknotes in Puerto Rico
1 peso 1817 coin in Chile
Was there anything before them?