Johann Ludwig Schönleben began fervently defending the truth about the Immaculate Conception of Mary during his Jesuit period. He became more involved in Mariology after leaving the order. In 1659 he published two books of his Orbis universi votorum (Vows of the Entire World). His most important Mariological works, Vera ac sincera sententia (A True and Honest Opinion, 1668/1670) and Palma virginea (The Virgin Palm, 1671), were printed in Salzburg. Due to their polemical tone, and in spite of their otherwise impeccable theological integrity, both works were included on the Index librorum prohibitorum. The same fate befell the two editions (1680, 1681) of De officio immaculatae conceptionis Deiparae antiquissimo et devotissimo (The Oldest and Most Devout Service of the Immaculate Conception of the Mother of God), which were also prohibited. They came out anonymously, and the possibility of Schönleben’s authorship was first pointed out by Valvasor. Schönleben se je z mariologijo in vnetim zagovarjanjem resnice o Marijinem brezmadežnem spočetju začel ukvarjati že kot jezuit, dejavneje pa se ji je posvetil po izstopu iz reda. Leta 1659 sta v Celovcu izšli dve knjigi spisa Orbis universi votorum. Njegovi najpomembnejši mariološki deli, Vera ac sincera sententia (katerega prvo izdajo je leta 1668 izdal pod psevdonimom Balduinus Helenocceus, drugo leta 1670 pa s svojim pravim imenom) in Palma virginea (1671), sta bili natisnjeni v Salzburgu. Kljub siceršnji teološki neoporečnosti sta bili zaradi polemičnega tona pisanja uvrščeni na Indeks prepovedanih knjig. Enaka usoda je pozneje doletela dve izdaji spisa De officio immaculatae conceptionis Deiparae antiquissimo et devotissimo (1680, 1681), ki sta izšli anonimno, na možnost Schönlebnovega avtorstva pa je prvi opozoril Valvasor.
