There’s a lot of fascinating folklore around the robin and the wren. At the winter solstice, the Holly King is driven away and the Oak King takes his place until the summer. Similarly, I have read that the robin rules once the wren is vanquished in December.
Jean Harrowven writes in her book Origins of Rhymes and Sayings that ‘Who Killed Cock Robin?’ is about King William Rufus, killed in the New Forest by an arrow, citing his red hair or the blood on his breast as explanation.
There is also a poem by John Webster, as stark and beautiful as you would expect…
Call for the robin-redbreast and the wren,
Since o’er shady groves they hover
And with leaves and flowers do cover
The friendless bodies of unburied men.
Call unto his funeral dole
The ant, the field-mouse, and the mole
To rear him hillocks that shall keep him warm
And (when gay tombs are robb’d) sustain no harm;
But keep the wolf far thence, that’s foe to men,
For with his nails he’ll dig them up again.