The town grew up around this point, and the bridge, or whatever preceded it, was not incidental to that growth; it was probably the reason the town is where it is.

The earliest written mention of the bridge dates to 1569, when it appears in a document placing it near the local churchyard. By that point it already had a name familiar enough to need no further explanation, suggesting the crossing had been a fixed feature of the town for some time before anyone thought to write it down. A fording point, a natural shallow where the river could be crossed on foot or with livestock, almost certainly preceded any formal structure. When the 1641 Survey of Mullingar was compiled, the bridge served as a straightforward geographical reference point, used to locate a mill called Mullynnehouny, which lay to the north of it, with Austin Friars Street to the south and what was then simply described as the town to the west. The survey was not describing the bridge as anything remarkable; it was using it the way you use a landmark so well known that it needs no explanation. That incidental quality is part of what makes it interesting. The date of the first bridge's construction remains unknown, and nothing in the surviving record fills that gap.