After newly unsealed court filings revealed George Papadopoulos pleaded guilty to lying to the FBI about his contacts with Russians, President Trump quickly downplayed his relationship to his campaign's foreign policy adviser. "Few people knew the young, low level volunteer named George, who has already proven to be a liar," he tweeted Tuesday.

But the records show Papadopoulos was actually in frequent touch with senior campaign officials about his efforts to connect Trump's team with the Russian government. Papadopoulos was also offered damaging information on opponent Democrat Hillary Clinton from people he believed were connected to the Kremlin, according to the documents.

The charges against Papadopoulos, who has since become a "proactive cooperator" with federal authorities, are one of Robert Mueller's first prosecutions in his wide-ranging federal investigation into Russia's interference in the presidential election. A federal jury also indicted former Trump campaign chair Paul Manafort and his associate Rick Gates on charges that they secretly worked on behalf of pro-Russian factions in Ukraine, then laundered millions of dollars in profits through foreign bank accounts.

More:Denying Russia collusion, Trump calls campaign aide George Papadopoulos a 'liar' and 'low level volunteer'

More:Ex-Trump campaign adviser George Papadopoulos pleads guilty to lying to FBI about Russian contacts

More:Mueller's bombshell: Special counsel charges Manafort, Gates and reveals aide's Russia contacts

The court documents refer to certain people involved in the discussions using pseudonyms including "Professor," "Campaign Supervisor," "Russian MFA Connection," and "Female Russian National."

We reviewed the "Statement of the Offense" and an FBI agent's affidavit that were unsealed Monday for new details about communications involving Trump's campaign and Russia.

Here's a comprehensive timeline:

Early March 2016

Papadopoulos, who was living in London at the time, learned he would be a foreign policy adviser for the Trump campaign.

March 6, 2016

Papadopoulos spoke with a Trump campaign official identified in court records as just "Campaign Supervisor." Based on that conversation, the documents said, Papadopoulos understood that a principal foreign policy focus of the Trump campaign was an improved U.S. relationship with Russia.

March 14, 2016

While traveling in Italy, Papadopoulos met an individual who was a professor based in London, identified in court records as the "Professor." Initially, the Professor seemed uninterested in Papadopoulos. However, after Papadopoulos informed the Professor he had joined the campaign, the Professor appeared to take great interest, the documents said.

Papadopoulos was interested in the Professor because, among other reasons, the Professor claimed to have substantial connections with Russian government officials, which Papadopoulos thought could increase his importance as a policy adviser to the Trump campaign.

March 19, 2016

Hillary Clinton campaign chairman John Podesta's email is hacked, according to a later report from Vice.

March 21, 2016

In a meeting with The Washington Post editorial board, Trump provides a list of five foreign policy advisers: Walid Phares, Carter Page, Joe Schmitz, ret. Lt. Gen. Keith Kellogg – and George Papadopoulos.

"George Papadopoulos, he’s an energy and oil consultant, excellent guy," Trump said.

March 24, 2016

Papadopoulos met with the Professor in London. The Professor brought with him a woman — identified in court records as the “Female Russian National” — who was introduced to Papadopoulos as a relative of Russian President Vladimir Putin with connections to senior Russian government officials.

Papadopoulos emailed Trump campaign officials, including the Campaign Supervisor and several members of the campaign’s foreign policy team, stating: “just finished a very productive lunch with a good friend of mine, ["The Professor”]... — who introduced me to both Putin’s niece [“Female Russian National”] and the Russian Ambassador in London — who also acts as the Deputy Foreign Minister.”

Papadopoulos added: “The topic of the lunch was to arrange a meeting between us and the Russian leadership to discuss U.S.-Russia ties under President Trump. They are keen to host us in a ‘neutral’ city, or directly in Moscow. They said the leadership, including Putin, is ready to meet with us and Mr. Trump should there be interest. Waiting for everyone’s thoughts on moving forward with this very important issue.”

The Campaign Supervisor responded that he would “work it through the campaign,” but that no commitments should be made at that point. The Campaign Supervisor added: “Great work.”

March 31, 2016

Papadopoulos attended a “national security meeting” in Washington with then-candidate Trump and other foreign policy advisers for the campaign.

When Papadopoulos introduced himself to the group, he said he had connections that could help arrange a meeting between then-candidate Trump and Putin.

After his trip to Washington, documents show Papadopoulos worked with the Professor and the Female Russian National to arrange a meeting between the campaign and the Russian government, and took steps to advise the Trump campaign of his progress.

Early April 2016

Papadopoulos sent multiple emails to other members of the campaign’s foreign policy team regarding his contacts with “the Russians” and his “outreach to Russia.”

April 10, 2016

Papadopoulos emailed the Female Russian National, re-introducing himself and noting that “[w]e met with [“Professor”] in London. The reason for my message is because [“Professor”] sent an email that you tried contacting me."

He added: “It would be a pleasure to meet again. If not, we should have a call and discuss some things.” He ended the email with his mobile number and a request for Female Russian National’s mobile number.

April 11, 2016

The Female Russian National responded to Papadopoulos’ April 10 email, saying that she was “now back in St. Petersburg” but “would be very pleased to support your initiatives between our two countries and of course I would be very pleased to meet you again.”

Papadopoulos responded, copying The Professor, saying: “I think a good step would be for me to meet with the Russian Ambassador in London sometime this month.” Papadopoulos said he would “like to discuss with him, or anyone else you recommend, about a potential foreign policy trip to Russia."

The Professor responded to Papadopoulos later that same day: “This is already been agreed. I am flying to Moscow on the 18th for a Valdai meeting, plus other meetings at the Duma.” (It's unclear what Valdai refers to in this context, though there is a Moscow think tank called the Valdai Discussion Club.)

The Female Russian National responded that she had "already alerted my personal links to our conversation and your request…As mentioned we are all very excited by the possibility of a good relationship with Mr. Trump. The Russian Federation would love to welcome him once his candidature would be officially announced.”

April 12, 2016

A person identified in court records as "Russian MFA Connection" emailed Papadopoulos. MFA refers to the Russia Ministry of Foreign Affairs.

The person said: “I have already alerted my personal links to our conversation and your request. The Embassy in London is very much aware of this. As mentioned we are all very excited about the possibility of a good relationship with Mr. Trump. The Russian Federation would love to welcome him once his candidature would be officially announced.”

April 18, 2016

The Professor emailed Papadopoulos, saying that he had a “long conversation in Moscow with my dear friend [“Russian MFA Connection”] …about a possible meeting between the two of you. [“Russian MFA Connection”] is ready to meet with you in London (or USA or Moscow). I am putting the two of you in touch to discuss when and where this potential meeting can actually take place.”

Russian MFA Connection was copied on the email.

Papadopoulos responded by offering to “try and come to Moscow” and setting up a Skype call with the Russian MFA Connection for 3:00 p.m. “Moscow time.”

Over the next several weeks: Papadopoulos and the Russian MFA Connection had multiple conversations over Skype and email about setting “the groundwork” for a “potential” meeting between the campaign and Russian government officials.

April 22, 2016

The Russian MFA Connection sent Papadopoulos an email thanking him “for an extensive talk” and proposing “to meet in London or in Moscow.”

Papadopoulos replied by suggesting that “we set one up here in London with the Ambassador as well to discuss a process moving forward.”

April 25, 2016

Papadopoulos emailed a senior policy adviser for the campaign: “The Russian government has an open invitation by Putin for Mr. Trump to meet him when he is ready. The advantage of being in London is that these governments tend to speak a bit more openly in ‘neutral’ cities.”

April 26, 2016

Papadopoulos met the Professor for breakfast at a London hotel. During this meeting, the Professor told Papadopoulos that he had just returned from a trip to Moscow where he had met with high-level Russian government officials. The Professor told Papadopoulos that on that trip he learned that the Russians had obtained “dirt” on then-candidate Clinton. The Professor told Papadopoulos – as Papadopoulos later described to the FBI – that “they [the Russians] have dirt on her”; “the Russians had emails of Clinton”; “they have thousands of emails.”

After April 26, 2016

Papadopoulos continued to correspond with Trump campaign officials, and continued to communicate with the Professor and the Russian MFA Connection, in an effort to arrange a meeting between the campaign and the Russian government.

April 27, 2016

Papadopoulos emailed the senior policy adviser: “Have some interesting messages coming in from Moscow about a trip when the time is right.”

Papadopoulos also emailed a high-ranking official of the Trump campaign — identified in court records as “High-Ranking Campaign Official” — “to discuss Russia’s interest in hosting Mr. Trump. Have been receiving a lot of calls over the last month about Putin wanting to host him and the team when the time is right.”

April 29, 2016

Papadopoulos wrote in an email to the Russian MFA Connection: “I am now in the process of seeing if we will come to Russia. Do you recommend I get in touch with a minister or embassy person in Washington or London to begin organizing the trip?”

The Russian MFA Connection replied: “I think it would be better to discuss this question with [The Professor].” Papadopoulos responded: “Ok. I called him.”

April 30, 2016

Papadopoulos thanked the Professor for his “critical help” in arranging a meeting between the Trump campaign and the Russian government. “It’s history making if it happens," he said.

May 4, 2016

The Russian MFA Connection sent an email to Papadopoulos and the Professor, saying: “I have just talked to my colleagues from the MFA. The[y] are open for cooperation. One of the options is to make a meeting for you at the North America Desk, if you are in Moscow.”

Papadopoulos responded that he was “[g]lad the MFA is interested.”

Papadopoulos forwarded the Russian MFA Connection’s email to the High-Ranking Campaign Official, adding: “What do you think? Is this something we want to move forward with?”

May 5, 2016

Papadopoulos had a phone call with the Campaign Supervisor, and then forwarded the May 4 MFA Email to him, adding to the top of the email: “Russia updates.”

May 8, 2016

“Russian MFA Connection” emailed Papadopoulos and “The Professor” about putting Papadopoulos in touch with the “MFA head of US desk.”

In subsequent weeks, “Russian MFA Connection” set up Skype calls with Papadopoulos and discussed, among other things, the fact that “Russian MFA Connection” reported “good reaction from the US desk at MFA.”

May 13, 2016

"The Professor” emailed Papadopoulos with “an update” of what they had discussed in their “recent conversations."

The Professor said: “We will continue to liaise through you with the Russian counterparts in terms of what is needed for a high level meeting of Mr. Trump with the Russian Federation.”

May 14, 2016

Papadopoulos emailed the High-Ranking Campaign Official and said the “Russian government ha[s] also relayed to me that they are interested in hosting Mr. Trump.”

May 21, 2016

Papadopoulos emailed an unnamed Trump campaign official, with the subject line “Request from Russia to meet Mr. Trump.” The email included the May 4 email Papadopoulos received from the Russian MFA Connection and added: “Russia has been eager to meet Mr. Trump for quite sometime and have been reaching out to me to discuss.”

The campaign official forwarded that email to another Trump campaign official (without including Papadopoulos) saying: “Let[']s discuss. We need someone to communicate that DT is not doing these trips. It should be someone low level in the campaign so as not to send any signal.”

June 1, 2016

Papadopoulos emailed the High-Ranking Campaign Official and asked about Russia. The High-Ranking Campaign Official referred him to the Campaign Supervisor because “[h]e is running point.”

Papadopoulos then emailed the Campaign Supervisor, with the subject line “Re: Messages from Russia."

“I have the Russian MFA asking me if Mr. Trump is interested in visiting Russia at some point," Papadopoulos said. "Wanted to pass this info along to you for you to decide what’s best to do with it and what message I should send (or to ignore).”

From mid-June through mid-August 2016, Papadopoulos pursued an “off the record” meeting between one or more campaign representatives and “members of President Putin’s office and the MFA.”

June 19, 2016

After several email and Skype exchanges with the Russian MFA Connection, Papadopoulos emailed the High-Ranking Campaign Official, with the subject line “New message from Russia."

“The Russian ministry of foreign affairs messaged and said that if Mr. Trump is unable to make it to Russia, if a campaign rep (me or someone else) can make it for meetings? I am willing to make the trip off the record if it’s in the interest of Mr. Trump and the campaign to meet specific people," he said.

June 2016

Paul Manafort takes over as Trump’s campaign manager after Corey Lewandowski’s departure.

July 7, 2016

Carter Page — a member of the Trump campaign's national security advisory committee — gives a speech at the New Economic School in Moscow, a trip made with approval from the campaign.

July 14, 2016

Papadopoulos emailed the Russian MFA Connection and proposed “a meeting for August or September in the UK (London) with me and my national chairman, and maybe one other foreign policy adviser and you, members of President Putin’s office and the MFA to hold a day of consultations and to meet one another. It has been approved from our side.”

July 15, 2016

Papadopoulos sent a private Facebook message to the Facebook account identified with Russian MFA Connection, stating: “We can chat on this, this weekend if you can’t tonight.” Russian MFA Connection messaged back a Facebook “thumbs up.”

July 21, 2016

Papadopoulos sent another private Facebook message to Russian MFA Connection.

“How are things [Russian MFA Connection]? Keep an eye on the speech tonight. Should be good," he said.

Trump gives Republican nomination acceptance speech at the RNC in Cleveland, Ohio.

July 18-21, 2016

The Republican National Convention was held in Cleveland.

At the convention, Russian Ambassador Sergey Kislyak spoke with then-Senator Jeff Sessions, who was chairman of the campaign's national security advisory committee, along with committee member Carter Page and J.D. Gordon, who managed the committee as the campaign's director of national security.

July 22, 2016

On the Friday before the Democratic National Convention began, WikiLeaks released emails dating from January 2015 to May 2016 believed to have been stolen from the DNC by Russian state actors.

Papadopoulos messaged Russian MFA Connection on Facebook to ask whether Russian MFA Connection knew a particular individual with extensive ties to Russian-based businesses and persons.

Papadopoulos asked Russian MFA Connection “[i]f you know any background on him that is noteworthy before I see him, kindly send my way.”

In the following weeks, Papadopoulos continued further communications regarding a potential “off the record” meeting with Russian officials.

August 15, 2016

Following several weeks of communications regarding a potential "off the record" meeting with Russian officials, the Campaign Supervisor told Papadopoulos that “I would encourage you” and another foreign policy adviser to the campaign to “make the trip, if it is feasible.”

The trip proposed by Papadopoulos did not take place.

September 30, 2016

The Russian news agency Interfax publishes an interview with Papadopoulos in which he expresses critical views toward U.S. sanctions against Russia.

October 1, 2016

Papadopoulos sent The Professor a private Facebook message with a link to an article from Interfax.

October 7, 2016

Anti-secrecy site Wikileaks begins publishing John Podesta’s emails, which had been hacked in March 2016.

– Julia Fair contributed from Washington

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