He knew in the hour he died
That his heart had never spoken
In eighty years of days.
O for the tall tower broken
Memorial is denied:
And the unchanging cairn
The pipes could set ablaze
An aaronsrod and blossom.
They stood by the graveside
A ciarn is an ancient burial mound, a pile of stones, appropriate to a poem about the death of a once formidable man. That it is ‘unchanging’ implies the grandfather’s implacability. 

Elegy for My Fathers Father