Excessive devotion and enthusiasm in religious observance were superstitio, in the sense of "doing or believing more than was necessary", to which women and foreigners were considered particularly prone. The boundaries between religio and superstitio are perhaps indefinite. The famous tirade of Lucretius, the Epicurean rationalist, against what is usually translated as "superstition" was in fact aimed at excessive religio. Roman religion was based on knowledge rather than faith, but superstitio was viewed as an "inappropriate desire for knowledge"; in effect, an abuse of religio.

What was excessive religious fervor in Rome's religions?