The main entry notes that claims of Christian borrowing from mystery religions are "a staple of popular polemic," and much of that polemic today traces, directly or through several removes, to a single nineteenth-century book whose specific factual claims modern scholarship has found almost entirely unsupported by any actual ancient source.
Kersey Graves, an American Spiritualist and freethinker, published The World's Sixteen Crucified Saviors in 1875, claiming sixteen figures from world religions, including Krishna, Buddha, Mithra and Horus, were each crucified and resurrected before Christianity, a book that provided almost no citations to primary sources and has been shown by later historians, examining the actual ancient record for each figure individually, to contain claims not found in any surviving ancient text for the great majority: Krishna is not crucified in any Hindu scripture, Mithras is not resurrected in any surviving Mithraic source, and several of Graves's supposed parallels appear to have been invented outright.
Despite this, Graves's claims, rather than the more cautious scholarly categories developed later by Frazer and criticized further by Jonathan Z. Smith as the main entry describes, continue to circulate widely in popular literature, repeated as established fact by writers who have not traced them to their unsourced origin. Professional historians with no religious commitment to defend have independently debunked Graves's claims on ordinary evidential grounds, the same grounds on which Smith criticized Frazer's more careful category, so the popular "many crucified saviors" claim is actually further from scholarly credibility than the dying-and-rising god category the main entry already describes as substantially dismantled.