By around 1840, when the antiquarian John O'Donovan visited, only a fragment of the chancel remained, measuring roughly eighteen feet by eleven, reduced almost to its foundations and retaining a single small window in the south wall. Today even that remnant has vanished, leaving a rectangular walled graveyard on a gentle south-facing slope in County Wexford as the principal marker of a place that was once, for a few centuries, genuinely significant. What survives above ground instead are twelve granite grave-markers with solid ringed heads, their design almost certainly echoing the base and head of a granite high cross that still stands about 120 metres to the north, the sole physical remnant of the monastery that once occupied this ground.

The name Taghmon is an anglicisation of Teach Munna, meaning Munna's house, and the original Irish place-name was Achad Liathdrum, Field of the Grey Ridge. St. Munna is said to have founded a monastery here in the late sixth century, dying at the site in 635. His background was well-connected: through his mother Feidhealm he was linked to Niall Naoighiallach, the high king known as Niall of the Nine Hostages, and he had studied at Kilmore in Co. Cavan and Devenish in Co. Fermanagh before being associated with Colum Cille of Iona. The monastery he established eventually became a rival to Ferns, the ecclesiastical centre of the Uí Chinnselagh dynasty, and in 814 or 816 a battle was fought between the two communities, or their supporters, in which 400 people died. Viking raiders struck in 824, but Taghmon apparently fought them off between 825 and 827. A further Viking raid in 917 may have been decisive. The monastery seems to have been defunct by the mid-eleventh century, a decline possibly connected to the falling fortunes of its patrons, the Síl Máeluidir, within the Uí Chinnselagh dynasty. Abbatial deaths had been recorded there from 777 to 953; after that, silence.

The graveyard is still in use, and the ringed grave-markers are worth examining closely. The solid ring, rather than the open wheel-head more common on tall free-standing high crosses, is an unusual local form, and the suggestion that these relatively modest markers took their cue from the fragmentary high cross to the north gives the whole site an odd kind of internal coherence: a community of the dead still, in some sense, oriented towards a monastery that disappeared roughly a thousand years ago.