(CNN) House Intelligence Chairman Devin Nunes stepped aside from leading the House investigation into Russia's meddling in the US election Thursday, capping a chaotic ride that began with a secret trip to the White House grounds that would eventually form the core of President Donald Trump's counter-offensive.

In just 16 days, Nunes fell from leading the House's Russia's probe to becoming the target of a House probe himself, as House Ethics investigators announced their inquiry into whether Nunes illegally revealed classified intelligence.

It marked a stunning change for the former cattle rancher from Central California who drew as much heat himself as the Russia probe itself. Nunes' decision to present intelligence gathered by the White House, almost derailed the House investigation, but instead Nunes was forced aside.

The timeline of Nunes' fall starts the day after the stunning public hearing Nunes led where FBI Director James Comey announced that federal investigators have been examining ties between the campaign of President Donald Trump and Russian operatives since last July.

-- Nunes takes a secret trip to the White House grounds , where he reviews intelligence gathered for him by two top White House staffers that Trump and his supporters would say backs the President's claims that he was a victim of surveillance. The intelligence will later form the core of Trump's counter-offensive against the Russia investigations.

Wednesday, March 22 -- Nunes calls a news conference where he reveals that he has seen new evidence that communications from Trump's transition aides -- and possibly Trump himself -- were picked up in "incidental" collection by US intelligence. Nunes travels to the White House to personally brief Trump on his findings (although it remains unclear why Trump's staff did not directly brief him on the findings they presented to Nunes).

Thursday, March 23 -- Nunes apologizes to other members of the House Russia investigation for not showing them the intelligence he viewed before going to Trump with it. Nunes promises lawmakers they will soon get copies of the same reports he viewed.

Meanwhile, former Trump campaign chairman Paul Manafort, former Trump foreign policy adviser Carter Page and former Trump adviser Roger Stone said they would gladly testify before investigators.

Monday, March 27 -- House Democratic Leader Nancy Pelosi and Rep. Adam Schiff, the lead Democrat on the House Russia investigation, -- House Democratic Leader Nancy Pelosi and Rep. Adam Schiff, the lead Democrat on the House Russia investigation, call on Nunes to recuse himself , following reports from CNN and others that Nunes secretly gathered his intelligence on the White House grounds. Nunes, meanwhile, cancels all meetings of the House intelligence committee for the week -- the newest sign that the House Russia investigation is close to running off the rails.

Nunes says he sees no reason to step aside.

Tuesday, March 28 -- House Russia investigators were supposed to have their second public hearing with Yates -- instead Republicans and Democrats are locked in a power struggle over who will testify. Comey alerts House Russia investigators he won't return to testify before them if they can't agree on a plan.

Wednesday, March 29 -- House Speaker Paul Ryan continues saying in public that he supports Nunes and will not ask for him to step aside. -- House Speaker Paul Ryan continues saying in public that he supports Nunes and will not ask for him to step aside. But in an interview with CBS , Ryan keeps Nunes at arm's length -- downplaying how much Nunes told him about the intelligence he gathered at the White House.

Thursday, March 30 -- Nunes and Schiff talk for the first time since the ranking Democrat said the chairman had to be removed from the investigation. Flynn's lawyer, a former "Never Trump" Republican, announces that Flynn is ready to testify before House and Senate investigators -- Nunes and Schiff talk for the first time since the ranking Democrat said the chairman had to be removed from the investigation. Flynn's lawyer, a former "Never Trump" Republican, announces that Flynn is ready to testify before House and Senate investigators in return for a guarantee of immunity from prosecution

Friday, March 31 -- CNN and others report that Nunes' sources were not whistleblowers, but -- CNN and others report that Nunes' sources were not whistleblowers, but instead top staff on the National Security Council -- a former Nunes staffer, Mike Ellis, and a close Flynn ally, Ezra Cohen-Watnick. Schiff travels to the White House to review the intelligence Nunes saw and emerges Friday evening, accusing Nunes and the White House engaging in sleight of hand to distract investigators from the Russia investigation.

Schiff meets briefly with Trump at the White House that evening. Trump promises him that all members of the House intelligence committee will be allowed to view the same intelligence, Schiff says.

Monday, April 3 -- Nunes responds to the growing chorus of critics calling for him to step aside: -- Nunes responds to the growing chorus of critics calling for him to step aside: "I don't really listen to what anyone says." Nunes says the Russia investigation is moving along fine and that witnesses could be called in for interviews as the second week of the House's Easter Recess.

The White House, meanwhile, grasps hold of news that the intelligence Nunes viewed at the White House shows former National Security Adviser Susan Rice approved the "unmasking" of Trump aides in intelligence reports -- the charge that becomes the centerpiece of Trump's counter-offensive against the Russia investigations.

Tuesday, April 4 -- Ryan meets with Republicans on the House intelligence committee. Later that day, Nunes stops answering questions from the press. Pelosi's staff travels to the White House to view the intelligence reports. House Democrats are briefed on the contents of the intelligence reports that Nunes reviewed.

Wednesday, April 5 -- Nunes meets with Ryan that night, where he says he will step aside the next day. A Ryan aide refuses to say whether Ryan asked for Nunes to leave the Russia investigation.

Trump tells the New York Times that he thinks Susan Rice committed a crime, but says he doesn't want to talk about the intelligence documents that would show that, when asked if he would declassify them.

Thursday, April 6 -- Shortly after 9:30 a.m., Nunes announces he is stepping aside and the House ethics committee announces it is investigating whether Nunes illegally revealed classified information.

A spokesperson for Trump said the White House will not comment on Nunes: "This is an internal matter for the House."