In 1990, São Tomé became one of the first African countries to undergo democratic reform, and changes to the constitution – the legalization of opposition political parties – led to elections in 1991 that were nonviolent, free, and transparent. Miguel Trovoada, a former prime minister who had been in exile since 1986, returned as an independent candidate and was elected president. Trovoada was re-elected in São Tomé's second multiparty presidential election in 1996.