Former New York mayor Rudolph W. Giuliani sits at the center of President Trump’s extended effort to elicit politically useful dirt from Ukraine. Giuliani was leading Trump’s efforts from outside the White House, though he also served as point person for administration officials. Without Giuliani’s agitation, Trump probably still would have sought to compel Ukraine to launch the investigations he asked for during his July 25 call with Ukrainian President Volodymyr Zelensky — but not necessarily.

As attention has turned to the Trump-Giuliani effort over the past few weeks, we’ve learned a lot more about the galaxy of individuals surrounding Giuliani and his efforts. There are so many actors at this point, and so many curious incidents with which they’ve been involved, in fact, that it’s worth walking through the sprawling, complicated set of relationships.

At its heart is the itself-odd relationship between Trump and Giuliani. Giuliani is Trump’s personal attorney, though earlier this month, Trump seemed to distance himself from that relationship. That’s part of a pattern, too. When Trump wants to invoke attorney-client or executive privilege, individuals are readily included on the president’s team. When they’re politically problematic, Trump pushes them away.

We saw that last week with Lev Parnas and Igor Fruman, two associates of Giuliani’s whom Trump quickly disavowed after their arrests on charges of campaign finance violations. Both had been photographed with Trump, including a photo of Parnas with Trump in the White House. To hear Trump tell it, though, Parnas and Fruman may have just been fans lucky enough to score a selfie.

The first time Parnas and Fruman were looped into the Ukraine situation, though, was when the House committee in charge of the Trump impeachment inquiry reached out to them for information about their work. Those requests were elevated to subpoenas after their attorney, John Dowd, informed the committee that neither witness would be able to provide the requested information.

In that letter, Dowd — himself once part of Trump’s legal team — established a specific relationship between Parnas, Fruman and Giuliani: Fruman and Parnas assisted Giuliani in his work for Trump while also enjoying his representation in their own business interests. The neat effect? They had attorney-client privilege with Giuliani and, potentially, with Trump. (Dowd recently stopped representing Fruman.)

But Dowd also connected them to other attorneys: Joseph diGenova and Victoria Toensing, a husband-wife team who are Fox News regulars. The pair had been rumored as possible additions to Trump’s legal team earlier this year, but that never came to fruition. Parnas and Fruman, Dowd said, worked for diGenova and Toensing, too.

That’s interesting in part because diGenova and Toensing also represent a Ukrainian oligarch named Dmitry Firtash. On Friday, Bloomberg reported that diGenova and Toensing were working with Firtash as he worked to fight extradition to the United States. Bloomberg’s report identified at least two useful connections in that regard: diGenova and Toensing’s relationship with Giuliani (and therefore Trump), and their son Brady Toensing, who now works for the Justice Department.

The Justice Department, of course, was also the former employer of Giuliani, when he was a U.S. attorney. It is also reportedly investigating Giuliani and obtained the indictment against Fruman and Parnas.

(The younger Toensing was previously the head of the Vermont Republican Party. In that role, he pushed for an investigation into the wife of Sen. Bernie Sanders (I-Vt.) during the 2016 election.)

It’s worth noting another layer related to Firtash. His former attorney was Lanny Davis, who most recently earned national notoriety as the attorney for Michael Cohen — himself a former attorney for Trump. (And someone with his own problematic relationship to the Justice Department.)

That Bloomberg report offers insight into the way the Giuliani relationship with Ukraine evolved.

Giuliani’s debunked assertions about former vice president Joe Biden having been involved in untoward activity center on the 2016 firing of Ukraine’s then-general prosecutor, Viktor Shokin. Shokin says that he was fired because he was investigating a company for which Joe Biden’s son Hunter was working, though Shokin is the only official making that claim.

According to Bloomberg, people working with Firtash obtained a sworn statement in which Shokin leveled the allegations against Biden. Shokin had made similar claims previously, including to The Washington Post, and he had met with Giuliani before, as well. Nonetheless, Giuliani ended up with a copy of the statement, which, Bloomberg reports, was not intended for public consumption.

That Giuliani ended up with the statement raises a variety of questions, including about possible campaign finance violations. It also raises questions about how it got into the hands of the Hill’s John Solomon, who has repeatedly written stories undergirding the Giuliani-Trump allegations.

As the diagram above makes clear, though, the issue isn’t finding a stream connecting Giuliani to the Firtash probe — it’s isolating the correct one. An interesting development for Trump’s attorney, given that, when Firtash was represented by Davis, Giuliani argued that Firtash was tied to organized crime in Russia.

On Firtash’s behalf, Davis denied the allegation.

“Mr. Giuliani gets everything wrong, which is his custom,” Davis replied in a statement, “as we’ve seen over and over again when he lies about Donald Trump.”