For Albertus Magnus, see the De Potentia Daemonum (cited by Maury, Legendes Pieuses).

For Bonaventura, see the Comp.Theol.Veritat., ii, 26.

For Dante, see Purgatorio, c.5.On Bordone's picture, see Maury, Legendes Pieuses, p.

18, note.
The popes again and again sanctioned this doctrine, and it was amalgamated with various local superstitions, pious imaginations, and interesting arguments, to strike the fancy of the people at large.

A strong argument in favour of a diabolical origin of the thunderbolt was afforded by the eccentricities of its operation.