A person with great responsibilities, such as a king, is constantly worried.

From Shakespeare's Henry IV. Part II, 1597.

KING HENRY IV:

How many thousand of my poorest subjects
Are at this hour asleep! O sleep, O gentle sleep,
Nature's soft nurse, how have I frighted thee,
That thou no more wilt weigh my eyelids down
And steep my senses in forgetfulness?
Why rather, sleep, liest thou in smoky cribs,
Upon uneasy pallets stretching thee
And hush'd with buzzing night-flies to thy slumber,
Than in the perfumed chambers of the great,
Under the canopies of costly state,
And lull'd with sound of sweetest melody?
O thou dull god, why liest thou with the vile
In loathsome beds, and leavest the kingly couch
A watch-case or a common 'larum-bell?
Wilt thou upon the high and giddy mast
Seal up the ship-boy's eyes, and rock his brains
In cradle of the rude imperious surge
And in the visitation of the winds,
Who take the ruffian billows by the top,
Curling their monstrous heads and hanging them
With deafening clamour in the slippery clouds,
That, with the hurly, death itself awakes?
Canst thou, O partial sleep, give thy repose
To the wet sea-boy in an hour so rude,
And in the calmest and most stillest night,
With all appliances and means to boot,
Deny it to a king? Then happy low, lie down!
Uneasy lies the head that wears a crown.
Uneasy lies the head that wears a crown.