Dating from at least the 12th or 13th century, this ancient place of worship fell out of use in the early 1600s when ecclesiastical power shifted to the growing town of Ramelton on the mainland. The church's abandonment marked the end of centuries of religious life on this tiny island, accessible only at low tide.

When the new church was built in Ramelton during the early 17th century, it appears that at least one piece of the old island church made the journey across the water. According to the antiquarian G.H. Kinahan, writing in the 1880s, a small carved window head was removed from the Augnish church and incorporated into the newer building in town. This architectural fragment would have been one of the more elaborate features of the medieval church; such carved stonework was both expensive to produce and symbolically important.

Today, visitors to the area can still make out the location of the old church site on Augnish Isle, though little remains above ground. The story of the relocated window head serves as a tangible link between the island's medieval past and Ramelton's early modern development, illustrating how communities often recycled precious building materials whilst simultaneously preserving something of the sacred character of older religious sites.