In the mid-1800s, the Spanish dollar fell out of use in Mexico. The first minting of the coin peso was in 1866. Gradually, the gold and silver content of the coins was replaced with less expensive metals. In 1905, the gold content of the peso was reduced by nearly 50%. This was followed by a reduction in silver. From 1918 to 1977, the weight and fineness of all silver coins declined, until the last silver peso coins were issued in 1977.