copingstone

And I have undertaken the most difficult task, at the command -- for in such a case the timorous suggestion, hooped round by poignant apologies, is no less than a command -- of that human creature whom, in the little island under the north star, he held most dear of all -- his wife, to set a copingstone, a mere nothing in the air, upon the last work that came from his pen.

From Capetown to Ladysmith An Unfinished Record of the South African War G. W. Steevens

He had officiously detained the whole unhappy party, on the grounds that he wanted to re-examine everybody, and was thus keeping them miserably cooped up together over a horrible Sunday; and he had put the copingstone on his offences by turning out to be an intimate friend of Lord Peter Wimsey's, and having, in consequence, to be accommodated with a bed in the gamekeeper's cottage and breakfast at the Lodge.

Clouds of Witness Sayers, Dorothy L. 1927

Gregory's procedure was little less revolutionary than that of the King, but the claim to depose might appear as only a concomitant to the power already wielded by Popes in bestowing crowns, while for Gregory it had by this time become the copingstone in the fabric of those relations between Church and State which he and his party were building up.

The Church and the Empire, Being an Outline of the History of the Church from A.D. 1003 to A.D. 1304 1907