…why the last resting place of the Blessed Gisela of Bavaria in the convent church of Niedernburg is a place of pilgrimage for Hungarian citizens?

Gisela (born in 984 or 985 and died on 7^th of May 1060) was the sister of the German Emperor Henry II.
Gisela married the later King of Hungary Stephan in 995 a.d. at the age of 10 and became the Queen of Hungary.
She was renowned for bringing Christianity to pagan Hungary and set up many churches and convents there including Veszprem (the Gisela Chapel).
After Stephans’ death in the year 1038 she was hounded and imprisoned. In 1042 she returned to Bavaria to Passau where she became Abbes of the Benedictine convent Niedernburg until her death. Her tomb (late gothic) with the original flat headstone can be seen in the church.