Hildegard of Bavaria East-Franks, Princess of Germany

https://fmg.ac/Projects/MedLands/GERMANY,%20Kings.htm#LudwigIIleGer...

"1. HILDEGARD (828-23 Dec 856, bur [Zurich]). Abbess of Schwarzach-am-Main, near Wurzburg [after 844]-853. Abbess of Zurich 21 Jul 853. "Ludowicus…rex" made a donation to St Felix & Regula, Zurich confirming "filiæ nostræ Hildigardæ" as its abbess by charter dated 21 Jul 853[25]. The necrology of St Gall records the death "X Kal Jan" of "Hildigarda virgo Christi et domni Hludowici regis filia" specifying her burial "in ecclesia S Regulæ et Felicis martyrum Christi in castello Turago"[26]."
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Hildegard was originally buried in the crypt of Fraumünster in Zürich. Her remains/sarcophagus was moved to a more prominent location in the church in the 13th century. According to a spokesperson for the church, it is not clear where she lies today.

https://en.wikipedia.org/wiki/Hildegard_(abbess)
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Wikipedia (11 June 2022) Hildegard (abbess of Fraumünster)

Hildegard (828-December 23 856 or 859), was the daughter of Louis the German, Carolingian king of East Francia, and his wife Hemma. She was the abbess of Fraumünster, an abbey founded by her father.

Hildegard was the eldest child of Louis the German and the countess Hemma, born a year after their marriage.

In 844, she became the abbess of Münsterschwarzach in Bavaria, the Eigenkloster of the Carolingian court, founded in 780. On June 21, 853, Louis the German founded the abbey at Fraumünster, placing his daughter Hildegard as the abbess, while her younger sister Bertha succeeded her as abbess of Münsterschwarzach.

According to legend, the two sisters were living a cloistered life together at Baldern Castle. While travelling to Zurich to pray at the chapel of Saints Felix and Regula, they saw a deer with lighted antlers, who led them through the forest to a location beside the River Limmat. The sisters took this as a sign from God that a church was to be built at that location, and Louis the German obeyed this divine invitation. What is historically certain is that an abbey had been recently founded at Fraumünster, and this abbey with its considerable property and right to autonomous jurisdiction was entrusted to Hildegard.

Hildegard died December 23, 856 (some sources say 859). As before, her sister Bertha succeeded her as abbess of Fraumünster.

Hildegard is honored in the Catholic Church on 23 December.[1][2][3][4]

References
(in German) Gerhard Hartmann, Karl Schnith (Hrsg.), Die Kaiser. 1200 Jahre Europäische Geschichte. Marixverlag, Wiesbaden 2006, ISBN 3-86539-074-9, S. 70.
(in German) Peter Vogelsanger, Zürich und sein Fraumünster. Eine elfhundertjährige Geschichte (853–1956). NZZ Libro, Zürich 1994, ISBN 3-85823-515-6.