Presumably as a hangover from before we had ruling authorities, Mexico's currencies are split up between different eras:
Colonial - Real (1535-1821)
War of Independence - Real (1810-1822)
Empire of Iturbide - Real (1821-1823)
Republic - Real (1823-1897)
Empire of Maximiliano - Peso (1864-1867)
Republic - Peso (1863-1905)
Estados Unidos - Peso (1905-1992)
Estados Unidos - New Peso (1992-date)
Could we please combine the first four into Real (1535-1897) and the next three into Peso (1863-1992)? The ruling authorities appear to have been assigned, so there's no need for these divisions any more.
Former Numista referee for banknotes from Ireland, Northern Ireland, Scotland, Wales and Saint Helena.