Luiz Inácio Lula da Silva was inaugurated on Sunday, capping a triumphant return to Brazil's presidency 12 years after leaving office and less than two years after the corruption convictions that sent him to prison were annulled.

The big picture: Lula, 77, would ordinarily have received the presidential sash from his predecessor, but outgoing President Jair Bolsonaro skipped the ceremony, telling supporters in a tearful farewell on Friday that "we will not throw in the towel. We may have lost the battle but not the war."

• For Lula's supporters, hundreds of thousands of whom were expected to attend the inaugural festivities, Sunday was a day of celebration.

Driving the news: Lula ran more on nostalgia for his previous tenure (2003-2010), when a commodities boom fueled an unprecedented reduction in poverty, than on a detailed platform for this one.

• Lula, who has declared that "Brazil is back" in the fight against climate change, is expected to immediately announce steps to protect the Amazon and shift course on other issues, like imposing stricter gun controls.

In his farewell on Friday, Bolsonaro did not acknowledge Lula's victory but did condemn an alleged plot by one of his supporters to set off a bomb in the capital city, Brasilia. Bolsonaro then flew to Florida.

• With tensions running high ahead of the transfer of power, Brazil's high court temporarily banned civilians from carrying guns in Brasilia.

Flashback: Lula left office as quite possibly, as former U.S. President Obama once quipped, "the most popular politician on earth." But as the economy slowed down and a massive corruption probe heated up, things quickly fell apart for his leftist Workers' Party.

• Lula's handpicked successor, Dilma Rousseff, was impeached and removed from office in 2016. One year later, Lula was convicted of corruption. While the charges were later thrown out on procedural grounds, they prevented Lula from challenging Bolsonaro in 2018.

What to watch: Brazil's society is sharply polarized and the economic outlook is far bleaker than when he was first in office.

• Still, Lula has big ambitions for regional integration and global leadership, in addition to his domestic agenda.

Go deeper: Lula looks to restore Brazil's tarnished global stature