That the description reads almost like a military inventory is not accidental. Saggart, known in Irish as Teach Sagard, spent much of the medieval period as a frontier settlement on the Dublin marches, the contested borderlands where English colonial authority frayed and Irish Gaelic lordships pressed constantly inward. For a place that now sits quietly within commuting distance of the capital, its past was notably turbulent.

After the English conquest, Saggart was absorbed into a cluster of royal manors alongside Newcastle Lyons, Esker, and Crumlin. A royal manor was a unit of land held directly by the crown, administered for rent and agricultural profit, and by 1332 a Provost of Saggart named Thomas Bretnagh was accounting for £32 3s. 4d. in rents covering farmland, burgage plots, a water mill, and the proceeds of a local court. Burgage plots were the standard land parcels granted to settlers in a medieval borough, typically running back from a main street in long thin strips. The street pattern that researchers Bradley and King identified in Saggart fits this model closely: a single linear main street intersected by a road running roughly north-west to south-east, with what appears to have been a triangular marketplace at the junction. That geometry of commerce and habitation still underlies the modern village, even if nothing announces it. The settlement was not peaceable. In 1471 to 1472, the Irish parliament ordered Saggart to be enclosed with defences after it had been wasted and burned by the O'Byrnes, O'Tooles, and a group recorded as the Goulranyles. The order was specific and logistical: eighty labourers from Balrothery, eighty from Coolock, eighty from Castleknock, and eight from Newcastle were each required to bring their own food, barrows, spades, and pickaxes. The walls were apparently not enough. In 1580, Fiach Mac Hugh O'Byrne, the formidable Wicklow chieftain, captured and burnt the town.

The Down Survey map of Newcastle Barony, compiled under William Petty's direction in 1657, depicts the Saggart settlement clustered around two tower houses and a third structure annotated simply as a stump of a Castle. Tower houses were the compact fortified residences typical of late medieval Ireland, essentially a tall rectangular keep offering defensible domestic space. The surviving terrier, a written description accompanying the map, matches the visual record almost word for word. Later in the century, in 1682, a grant to Thomas Den included provision for a weekly market and three yearly fairs, along with a court of pie poudre, an itinerant merchant's court empowered to settle trading disputes quickly. The village is straightforward to reach on the N81 south-west of Dublin, and the medieval street plan, though overlaid by later development, remains legible if you walk the main street and look at the way the older plots slope back from the road.