Honório Hermeto Carneiro Leão, the Marquis of Paraná (1801 – 1856) was a Brazilian statesman, diplomat, judge and monarchist during the period of the Empire of Brazil (1822–1889). As co-founder of the Brazilian Conservative Party, he championed liberalism, exceptionalism, state authority and a representative, parliamentary monarchy. Paraná had been schooled in his party's principles by Bernardo Pereira de Vasconcelos, who was renowned for his intellectual capacity and leadership. Appointed president of Rio de Janeiro province in 1841, Paraná helped put down a rebellion headed by the opposition Liberal Party in the following year. In 1843, he became the de facto first President of the Council of Ministers of Brazil, while concurrently serving as Minister of Justice (a position he had briefly held in 1833), but lost the office after a quarrel with the Emperor. In 1853, Paraná was appointed president of the Council of Ministers and headed a highly successful Cabinet credited with ushering in several vital reforms. On 3 September 1856, while still in office, he died unexpectedly of an unknown febrile condition. To this day, he is regarded as one of the most influential politicians of his time and one of the greatest statesmen in the history of Brazil.