The first third party in American history was the Anti-Masonic Party. There are numerous different political parties nowadays, however you may only be aware of the Democratic and Republican parties. This is thanks to the Anti-Masonic Party. This party was founded in reaction to the mysterious Freemasons organisation, which many political elites were members of, and its secrecy. The 1820s and 1830s were the party's only full years of existence. It emphasised egalitarianism and encouraged political transparency, which were both noteworthy developments for the early 19th century.
The first presidential nominating convention was organised by the anti-Masonic party in 1831. All major parties thereafter embraced that practise.