 In 1810, a Mexican Catholic Priest, Father Miguel Hidalgo y Costilla, who is also the Father of the Mexican nation, declared slavery abolished, but this was not official until the War of Independence finished.Pius VII joined the declaration of the Congress of Vienna, in 1815, urging the suppression of the slave trade.By now the major consistent opposition to this came from Spain and Portugal, to whose empires a continued supply of new slaves remained economically very important.