The Vatican said Saturday it was investigating an influential aide to late pope John Paul II, Cardinal Stanislaw Dziwisz, following allegations of abuse cover-ups.
Its embassy to Poland said the Holy See had sent Italian Cardinal Angelo Bagnasco to Poland from June 17 to 26 to look into the matter.
The visit's "goal was to verify reports, including those made public, of negligence on the part of Cardinal Stanislaw Dziwisz during his tenure as Krakow archbishop (2005-2016)," the Apostolic Nunciature, the official name for the embassy, said in a statement.
Dziwisz, now 82, worked alongside the Polish pontiff in the Vatican and later served as Archbishop of Krakow, before retiring in 2016.
"Bagnasco reviewed documents and held a series of meetings and will report back to the Holy See regarding the visit," the embassy added.
In November, Poland's bishops urged the Vatican to clarify Dziwisz's role, after a documentary broadcast by Polish network TVN24 raised questions about John Paul II's friend and secretary.
Then in March, a Polish state committee looking into paedophilia lodged a complaint with prosecutors alleging Dziwisz covered up clerical sex abuse in the southern diocese of Bielsko Biala and Zywiec.
The cardinal is also suspected of having hidden other cases of sexual abuse by clergy from the pope, including that of ex-US cardinal Theodore McCarrick.
The politically influential Catholic Church in devout Poland has recently been hit by a series of high profile cases of sexual abuse.
Since last year, the Vatican has sanctioned four Polish bishops for covering up paedophilia by members of the clergy.
It also sanctioned 97-year-old Polish cardinal Henryk Gulbinowicz, who has since died, after an unspecified probe that media reports said related to alleged sexual abuse.
Also last year, the Vatican announced the resignation of bishop Edward Janiak for cover-ups.
Slawoj Leszek Glodz, the archbishop of Gdansk known for his high-flying lifestyle and love of luxury, resigned last year following accusations that he had harassed priests and been silent on abuse claims.
On Monday, the Polish church is due to publish statistical data on sexual assaults against minors among the faithful.