1893, Rodolfo Lanciani, Pagan and Christian Rome, page 74:
The origin of the sæcular games seems to be this: In the early days of Rome the northwest section of the Campus Martius, bordering on the Tiber, was conspicuous for traces of volcanic activity.
1896C.E., Bagshaw, in The Archpriest Controversy, Nichols and Sons; part V, page #239:
De Rectoribus was made by some sæcular priests for some better vnited order.