Re-entering the Cathedral, he went up into the choir. The nave was mirrored in the surface of the brimming holy-water stoups, with the beginnings of the arches and some portions of the windows. But the reflection of the stained glass, though broken at the marble's rim, was continued farther on, upon the flagstones, like a many-coloured carpet. The brilliant daylight from without was projected throughout the whole length of the Cathedral in three enormous rays, through the three open doors. From time to time a sacristan would glide across the transepts, making the sideways genuflexion of a devotee in a hurry. The crystal lustres hung motionless from the ceiling. Within the choir a silver lamp was burning, and from the side chapels and the darker portions of the church there stole from time to time a sound like the exhalation of a sigh, accompanied by the noise of a grille shut to, that echoed on and on beneath the vaulted roof. Gustav Flaubert, Madame Bovary, Chapter 25.

Holy-water fonts or stoups have been found since time immemorial at the doors of churches. "All medieval churches had holy water stoups, but they were either destroyed or filled in at the Reformation," notes this site devoted to churches in Suffolk, England. (Horses could have been accommodated at All Saints, Hollesley.)

The web site of the Immaculate Conception Cathedral in Kansas City offers a primer on holy-water fonts as extensions of the baptismal font.

A contributor to a Catholic Information Network thread comments on an unfortunate trend that has accompanied the rise in popularity among modern liturgical engineers of the living-water baptismal tub: What I _don't_ like is removing all the _other_ holy water fonts from other entrances. In the Nashville cathedral, for example, they removed them all--but the parking lot is _behind_ the church, and almost no one enters by the front doors, which face the busiest street in the city. As a result, one has to travel the length of the church to bless oneself, or forgo it.