No masonry arch, no dressed stone; this was a wooden bridge, the first ever to span the river at this point, and its existence survived into the historical record largely because someone in 1549 thought it worth proposing a replacement.

The story, as recounted by O'Leary in 1892, begins with a petition sent to the English administration in December of that year. The proposal was for a new bridge over the Barrow positioned between Duiske Abbey, the Cistercian monastery that gave Graiguenamanagh much of its medieval character, and what the document calls the "Kavanaghs' Country", the Gaelic territory to the south and west held by the powerful Kavanagh clan. Nearby Tinnehinch Castle, on the Carlow bank, is thought to have guarded this earlier crossing, a reminder that bridges in this period were not just conveniences but strategic assets, points of control over movement and trade. The wooden bridge itself is known to have existed in some form, because when construction work began on the present navigation lock, roughly in the 1820s, labourers pulling up the riverbed found the old oak piles still embedded in the silt. Timber driven into a riverbed centuries earlier, preserved by waterlogged conditions, is one of the quieter ways the medieval past occasionally resurfaces.