The Clonmacnoise crosier, one of finest examples of early medieval metalwork
from Ireland, is described, and its history and provenance are thoroughly investigated for the first time. It is argued that the workshop that created it and
related material was located at Clonmacnoise and that abbot Tigernach Ua BrŠein (d.1088) may have been its commissioner. While there is no basis to
the story that it was found, along with another crosier, in Temple CiarŠn, its
iconography nevertheless suggests a link with that building and more generally
with Clonmacnoise. A crosier-head with a supposed Clonmacnoise provenance
is also discussed, its Clonmacnoise provenance is rejected, and it is proposed that it may have been deliberately broken and repaired in the sixteenth century. An attempt to trace its history has revealed the record of a theft of an Irish crosier-head from the British Museum in the nineteenth century, the fate of which remains unknown.