Early 12th Century Saints Honored by the Orthodox Church

I recently discovered and fell enamored with St. Hildegard von Bingen's hymns which led to looking up if she is pre or post schism and a source online (Western Rite FB Group) says that she and Francis of Assisi are two prominent figures that were at least not opposed from the Orthodox Church and that, up to 1200, well past the 1054 schism...a few saints from Catholicism were accepted and even venerated in some of the Orthodox jurisdictions. I am looking for more info on this topic as both her and St. Francis are I feel worthy of the title in Orthodoxy. Same with Gregorian Chant... Clearly, it was established and practiced way before the schism yet most traditional Eastern Orthodox churches avoid it while a few in the Western Rite embrace and frequently use it. A few others not under the WR but here in America use GC for special occasions. Thanks in Advance!! 💗🕊💗