The history of bell casting in Mexico goes back to 1520, when the bell that is still in the north tower of the Atlihuetzia Church in Tlaxcala, was casted. Of all the outstanding bells in Mexico, the most noteworthy are the 25 pertaining to the Metropolitan Cathedral, especially the one named "Our Lady of Guadalupe" weighing 13 tons -as a rule bronze is made out of an alloy of copper and tin. At the end of the 18th century there were hundreds of bells and their clamor, although musical, became unbearable. Bells were tolled both morning and night thus in 1766 the pealing of bells was restricted to law.