In 1683 Spaeth returned to Catholicism, which he defended and praised in a work entitled Judicium Amoris de Fundamentalibus Quibusdam, Qui Feruntur Erroribus Ecclesiæ Romanæ. But this reconciliation did not last.
Spaeth's return to Catholicism in 1683 was met with strong support, as he wrote about it in his work Judicium Amoris de Fundamentalibus Quibusdam, Qui Feruntur Erroribus Ecclesiæ Romanæ. Unfortunately, this reconciliation did not last long.