"Alumni" (seeAlumnus/a) is used here in the (correct) broad sense, to include people who have spent a notable period of their career studying at the institution, not in a narrower, legal sense of having officially "graduated" (for example in themedieval andearly modern periods it is often not known where or if people graduated).
In accordance withWikipedia:Categories criteria, the period spent studying at the institution should be notable enough to be mentioned in the article.
Please do not include recipients ofhonorary degrees in this category.