The decree issued by Pope Francis on Friday is an important step towards beatification, which will lead to the family being raised to saints in the Catholic church.
Pope Francis has recognised the martyrdom of a married couple with seven children who were executed by Nazi Germans for sheltering a Jewish family in their home in Poland during World War Two.
After launching an inquiry into the book’s origins, on Wednesday Poland’s culture minister Piotr Glinski said it had not been looted.
The Polish Foreign Ministry has launched an inquiry into the history of a book presented to Pope Francis by Emmanuel Macron, the French president.
During a private audience, Macron gifted the head of the Church the first French edition of Immanuel Kant's late 18th-century book Perpetual Peace: A Philosophical Sketch which some believe may have been looted during WWII.
President Andrzej Duda has invited Pope Francis to visit Poland.
Money donated by Pope Francis will be used to help migrants stuck on the border between Poland and Belarus, a Catholic Polish charity has said.
A beatification mass for Cardinal Stefan Wyszyński and Mother Elżbieta Czacka has gathered crowds of people at the Temple of Divine Providence in Warsaw, including Poland's top officials.
Pope Francis has accepted the resignation of Bishop Jan Tyrawa from the post of Bishop of Bydgoszcz due to accusations of covering up cases of paedophilia involving priests from his diocese.
Pope Francis has accepted the resignation of the bishop of the Polish diocese of Kalisz, western Poland, the Apostolic Nunciature in Poland reported on Saturday.