Thanks to some intrepid reporting from The Washington Post’s Greg Miller, Ellen Nakashima and Shane Harris, we now know that mysterious whistleblower complaint pertains to President Trump’s communications with a foreign leader and involves some kind of “promise” that was made.

Beyond that, it’s still a mystery. But the series of events that preceded the whistleblower complaint — along with Trump’s Oval Office disclosure of highly classified information to top Russian officials in 2017 and a pledge he said he would make to North Korean leader Kim Jong Un in June — has led to plenty of speculation.

Here are some notable events that occurred in the roughly two months before the whistleblower’s complaint on Aug. 12 -- and what we’ve since learned about the complaint:

June 11: Trump says he has received another “beautiful” letter from Kim. Trump also responds to news that Kim’s assassinated half brother was a CIA asset by saying he would tell Kim, “I wouldn’t let that happen under my auspices.”

June 14: Trump holds a phone call with Japanese Prime Minister Shinzo Abe.

June 18: Trump holds a call with Chinese President Xi Jinping about the ongoing U.S.-China trade war.

June 27-29: Trump attends the Group of 20 summit in Osaka, Japan. There, he holds bilateral meetings with foreign officials including Xi, Abe, Russian President Vladimir Putin, Saudi Crown Prince Mohammed bin Salman, Turkish President Recep Tayyip Erdogan, German Chancellor Angela Merkel, Indian Prime Minister Narendra Modi, Australian Prime Minister Scott Morrison and Brazilian President Jair Bolsonaro.

June 30: Trump meets with Kim in the demilitarized zone and briefly becomes the first sitting U.S. president to set foot on North Korean soil.

July 1: Trump holds a phone call with French President Emmanuel Macron, which covers topics including Iran, the G-20 and Trump’s meeting with Kim, according to a readout from the White House.

July 4: Trump holds a phone call with Egyptian President Abdel-Fattah el-Sissi.

July 6: Trump holds a call with British Prime Minister Theresa May.

July 8: Trump holds another call with Macron.

July 9: Trump meets with the emir of Qatar, Tamim Bin Hamad Al Thani.

July 11: Trump holds a phone call with Israeli Prime Minister Benjamin Netanyahu.

July 18: Trump meets with Netherlands Prime Minister Mark Rutte.

July 22: Trump meets with Pakistan Prime Minister Imran Khan.

July 25: Trump holds a phone call with Ukrainian President Volodymyr Zelensky.

July 31: Trump holds a phone call with Putin. The call is first reported by the Russians. The White House doesn’t confirm it till late that evening, saying Trump “expressed concern over the vast wildfires afflicting Siberia” and, “The leaders also discussed trade between the two countries.” The Russians, in a much more substantial readout, claim Trump and Putin also spoke about restoring full relations one day.

July 31: Trump meets with President Khaltmaagiin Battulga of Mongolia.

Aug. 2: The United States officially withdraws from the Intermediate-range Nuclear Forces (INF) Treaty with Russia, as had been previously announced.

Aug. 2: Trump announces a trade deal alongside European Union leaders Stavros Lambrinidis (the E.U. ambassador to the United States) and Jani Raappana (deputy head of mission for the Finnish presidency of the Council of the E.U.).

Aug. 2: Trump holds phone call with British Prime Minister Boris Johnson.

Aug. 8: After Trump’s pick of Rep. John Ratcliffe (R-Tex.) to replace Coats falls through, Trump announces Joseph Maguire would take on the role in an acting capacity. In doing so, he bypassed Sue Gordon, who had been Coats’s No. 2 at DNI and was a career intelligence official with bipartisan support. Gordon would also resign.

Aug. 9: A brief letter from Gordon to Trump is released. It makes her disappointment clear, “I offer this letter as an act of respect & patriotism, not preference,” she writes. “You should have your team."

Aug. 12: Whistleblower files complaint.

Sept. 13: House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) subpoenas Maguire to compel him to disclose the whistleblower complaint. Schiff says the complaint was determined to be “credible” by Intelligence Community Inspector General Michael Atkinson, but doesn’t say much more.

Sept. 17: Maguire says he will not testify or hand over the whistleblower complaint. Schiff said Maguire told him he couldn’t “because he is being instructed not to, that this involved a higher authority, someone above.”

Sept. 18: The Post reports the complaint involves Trump’s communications with a foreign leader and some kind of “promise” that was made.

Sept. 19: Atkinson is scheduled to brief members of the House Intelligence Committee in a closed-door session. Trump responded to the report in a series of tweets.

It’s tempting to draw the conclusion that this somehow involves the Russians, for a few reasons: What happened in 2017, the lack of disclosure about the call, and the fact that the Russians alluded to some kind of talks about normalizing relations (which the White House made no mention of). But that’s highly speculative at this point. And the White House is often cagey about these talks.

Ditto North Korea. Just because Trump seemed to allude to not spying on North Korea doesn’t mean he actually followed through. The idea that the United States would ever make such a promise and mean it is tough to swallow (even as we can’t really rule out anything these days).

Ukraine is also an interesting one, given Trump lawyer Rudy Giuliani has been trying to get the government there to look into the activities of Joe Biden’s son, Hunter Biden, who worked for a Ukrainian gas company. Giuliani had scheduled a trip to Ukraine but canceled it amid pressure. House Democrats are investigating whether Giuliani has been improperly applying pressure on the country to aid Trump’s 2020 reelection bid.

There are also a ton of interactions with foreign leaders over this period. The G-20 was about a month and a half earlier and included a bunch of bilateral meetings, including with the Saudi crown prince, whose relationship with the White House has also been controversial. In recent days, Trump responded to an attack on Saudi oil fields by suggesting the United States would defend the Saudis and that he was waiting for some kind of instructions from them.

These are, of course, only the meetings that are known publicly. We’ll keep filling out this timeline as we learn more.

Whistleblowers such as Daniel Ellsberg take personal risks to expose wrongdoing. (The Washington Post)