For Whom the Bell Tolls

No man is an island,
Entire of itself.
Each is a piece of the continent,
A part of the main.
If a clod be washed away by the sea,
Europe is the less.
As well as if a promontory were.
As well as if a manor of thine own
Or of thine friend's were.
Each man's death diminishes me,
For I am involved in mankind.
Therefore, send not to know
For whom the bell tolls,
It tolls for thee.

John Donne 

It is a precursor to today's more universalist sentiments, that all mankind is One, but that is stretching where he was starting from. Poets do that, I guess, reaching a bit farther than they even know themselves sometimes. Donne was raised in the ordering of society and Great Chain of Being, closer to feudalism than to Unitarian Universalists. We each had our ordained place in society, and the pieces fit together, so that the loss of any piece was felt throughout the whole. It didn't quite mean they were equal, however. 

That came later, and Donne likely helped drive it. 

Oops, forgot the second part. People were increasingly seeing themselves as individuals rather than as a part of a whole by the 1600s, a trend that began as early as the 1200s and continues to this day. Donne was speaking against that, cautioning people that they were not thoroughly independent, but interdependent.  But his interdependence was more hierarchical than we would be comfortable with today.