On June 27, 1877, two Polish-speaking girls of the village of Gietrzwałd in Warmia (then part of Prussia, undergoing the Kulturkampf — Bismarck's persecution of Catholic and Polish culture) saw the Blessed Virgin Mary in a maple tree by the parish church. The two visionaries were Justyna Szafryńska (13) and Barbara Samulowska (12). Over the next twelve weeks the apparitions repeated more than 160 times, with crowds eventually reaching tens of thousands.
Mary identified herself in Polish as 'the Immaculate Conception' (Niepokalanie Poczęta) — the only Vatican-recognised apparition in which she spoke Polish. Her message focused on the daily Rosary, prayer for vocations to the priesthood (the seminary at Pelplin had been closed by the Prussian government), and patient sufferance under persecution. The political significance was immediate: a Polish-speaking Marian apparition rallied Polish national-religious identity under Prussian suppression.
The apparitions were formally recognised by Bishop Józef Drzazga of Warmia on the centenary, September 11, 1977. Pope Francis confirmed full Vatican approval and elevated the Gietrzwałd shrine in 2024 — the second-most recent Marian apparition approval, after Laus 2008. The Sanctuary of Our Lady of Gietrzwałd is the second great Polish Marian pilgrimage after Częstochowa.