Manafort and Gates are facing multiple charges, including money laundering, conspiracy against the United States, and failure to disclose their lobbying activities for a foreign power. The pair entered a plea of not guilty in federal court on Monday.

Separately, onetime Trump campaign foreign policy advisor George Papadopoulos pleaded guilty to lying to investigators about his contact with Russian-linked interests.

The charges are the first major public developments in Mueller’s six-month-long investigation of Russian meddling in the 2016 election.

How did the investigation get to this point? Here’s a quick refresher:

October 7, 2016: Obama Administration confirms Russian involvement in Wikileaks email dump

About a month before Election Day, the Department Of Homeland Security and Office of the Director of National Intelligence announced that they believed Russia was involved with WikiLeaks’ publication of private emails from the Democratic National Committee (DNC) and Hillary Clinton campaign chairman John Podesta.

“These thefts and disclosures are intended to interfere with the U.S. election process,” a joint DHS-DNI statement read. “We believe, based on the scope and sensitivity of these efforts, that only Russia’s senior-most officials could have authorized these activities.”

January 6, 2017: DNI issues unclassified report on Russian meddling

As one of the last major actions of the Obama Administration, the Director of National Intelligence released a 25-page report just two weeks before Donald Trump’s inauguration. Titled “Assessing Russian Activities and Intentions in Recent U.S. Elections” the report confirmed the belief of the intelligence community that Russia was behind the hack targeting the DNC and Podesta’s emails. Moreover, the report concluded that Russia interfered in the U.S. election specifically to undermine Hillary Clinton’s campaign.

“Russia’s goals were to undermine public faith in the U.S. democratic process, denigrate Secretary Clinton, and harm her electability and potential presidency,” the report read. “We further assess Putin and the Russian Government developed a clear preference for President-elect Trump.”

In the weeks following the report, the Senate and House Intelligence Committees announced they would each investigate Russian interference in the election.

It was around this time that an unverified dossier emerged which reportedly outlined compromising information the Russian government may have collected about then-President elect Trump. The Washington Post reported last week that research for the dossier was funded in part by Hillary Clinton’s campaign and the DNC.

March 20, 2017: James Comey confirms the FBI is investigating Russian interference

James Comey, still serving as FBI Director at the time, told the House Intelligence Committee that the Department of Justice had authorized the FBI to investigate Russian interference in the 2016 election, including any potential collusion between Russia and the Trump campaign.

“The FBI, as part of our counterintelligence mission, is investigating the Russian government’s efforts to interfere in the 2016 presidential election and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government, and whether there was any coordination between the campaign and Russia’s efforts,” Comey said.

May 9, 2017: President Trump fires James Comey

President Trump unexpectedly announced that he was firing Comey, citing recommendations from top officials at the Department of Justice who were critical of Comey’s controversial handling of a probe into Hillary Clinton’s use of a private email server.

The explanation drew skepticism, as Trump had previously praised the Clinton investigation, and because Comey was overseeing the FBI’s investigation into Trump’s campaign.

“Regardless of the recommendation, I was going to fire Comey,” Trump later told NBC News anchor Lester Holt. “And in fact when I decided to just do it, I said to myself, I said you know, this Russia thing with Trump and Russia is a made-up story.”

May 17, 2017: Robert Mueller appointed as Special Counsel to lead Russia investigation

Following Comey’s ouster, former FBI Director Robert Mueller was appointed to lead the Office of Special Counsel, which was tasked with overseeing an independent investigation into Russian interference and has the power to file charges.

Mueller’s appointment came just days after the New York Times, citing a memo provided by Comey’s associates, reported that Trump had asked Comey for his loyalty during a private dinner. Comey reportedly demurred, instead telling the President he would be honest with him.

July 2017: Donald Trump, Jr. admits meeting Russia-linked lawyer

Initial reports said Donald Trump Jr. met with Russian lawyer Natalia Veselnitskaya in June to discuss U.S. adoptions of Russian children. But emails later published by Trump Jr. showed that he and his brother-in-law, Jared Kushner, met with Veselnitskaya after it was claimed that she had compromising information about Hillary Clinton. Trump, Jr. published the emails after the New York Times contacted him with copies of the messages.

October 4, 2017: Senate committee investigating Russia says it is still trying to hack election system

The Senate Intelligence committee told reporters in a press conference that they had not reached a conclusion about its probe into Russian interference in the election, but that the possibility of collusion between Russia and the Trump campaign was still a distinct possibility.”The Russian active measure efforts did not end on Election Day 2016,” Senator Mark Warner, ranking chairman of the Senate Intelligence Committee, told reporters.

October 30, 2017: Paul Manafort, Rick Gates indicted on 12 counts

Manafort and Gates were indicted on 12 counts, including money laundering, conspiracy against the United States and more, according to court filings. Manafort and Gates both pleaded not guilty; their bail figures were set at $10 million and $5 million, respectively.

The Office of the Special Counsel also revealed Monday that George Papadopoulos, formerly a foreign policy adviser to Trump’s campaign, had pleaded guilty to lying to the FBI in a January 2017 interview about his contact with a Russian professor. Papadopoulos was arrested in July and has been cooperating with investigators ever since.