A group of former senior European politicians who lobbied U.S. politicians as part of Paul Manafort’s unregistered foreign lobbying in the U.S. were identified by name this week in new filings from the Mueller investigation.

Why it matters: Manafort and his defense lawyers have said that the lobbying campaign was focused on just Europe, but some of the documents show members of the “Hapsburg group" attempted to influence the image of Ukraine’s president in the U.S. and that Manafort organized group members' visits to the U.S. to do so.

The Hapsburg group: Former Italian Prime Minister Romano Prodi, former Austrian Chancellor Alfred Gusenbauer, former Spanish NATO head Javier Solana, Belgian Judge Jean-Paul Moerman, head of the German Federal Chancellory Bodo Hombach, according to ABC.

Prodi, Gusenbauer, and Aleksander Kwasniewski, Poland’s president from 1995 to 2005, had all previously registered with the DOJ as lobbying in the U.S. for the Brussels-based European Centre for a Modern Ukraine , according to the Financial Times. Prodi, Gusenbauer, and Kwasniewski have each denied links with Manafort, per FT.

Be smart: Manafort has been accused of attempting to tamper with witness testimony along with a Russian aide, Konstantin Kliminck, through text messages. Some of the contents of the messages are revealed in the new filings, which show apparent efforts to convince people who worked with the Hapsburg group that the efforts focused on just the EU.

Details: The filing named Alan Friedman and Eckart Sager, who were previously identified as Person D1 and Person D2, according to ABC:

The filing named Alan Friedman and Eckart Sager, who were previously identified as Person D1 and Person D2, according to ABC: Manafort told Friedman, according to ABC: “We should talk. I have made clear that they worked in Europe."

The big picture: Manafort is facing a trial this fall on charges that he violated the Foreign Agents Registration Act after failing to register with the Department of Justice.

Previous filings from Special Counsel Robert Mueller have alleged that Manfort illegally financed the group's operations.

Rick Gates, who has pleaded guilty to conspiracy against the U.S. and making false statements to FBI agents and who worked on Trump's campaign as well, was also involved in the group’s lobbying efforts, per Politico.

Some of what happened:

Prodi met with Rep. Ed Royce and congressional staffers in March 2013 as part of the lobbying, per Politico.

Manafort reported some success as a result of the campaign, including preventing sanctions from being applied against Ukraine’s government.

Some requests of the Hapsburg group came at the direct request of the Ukrainian government and Yanukovych, including making a call to a senator.

The goal, per one of Manafort’s memos: "The strategy for the first quarter of 2013 was to heavily engage with the UGS [sic] and US Congress, using a strategy I built called 'Engage Ukraine' which focused the dialogue on positive key issues, and away from" political rival Yulia Tymoshenko, who was imprisoned in 2011.

Flashback: Mueller’s team described the group in February’s superseding indictment of Manafort as "a group of former senior European politicians to take positions favorable to Ukraine, including by lobbying in the United States.”

The intrigue: The names were revealed in a memo filed by the clerk un-redacted on Wednesday, but the memo was later re-filed in redacted form with those names hidden, per ABC. The un-redacted file was submitted with their names revealed inadvertently, according to CBS News.

One key quote: Mueller’s team called Manafort’s involvement in the lobbying "brazen efforts at corrupt persuasion.”