The following narrative poem by Longfellow provided the inspiration for Saki’s story ‘Ministers of Grace’ (originally published in The Bystander and later collected in The Chronicles of Clovis).

Robert of Sicily, brother of Pope Urbane
And Valmond, Emperor of Allemaine,
Apparelled in magnificent attire,
With retinue of many a knight and squire,
On St. John’s eve, at vespers, proudly sat
And heard the priests chant the Magnificat,
And as he listened, o’er and o’er again
Repeated, like a burden or refrain,
He caught the words, “Deposuit potentes
De sede, et exaltavit humiles”;
And slowly lifting up his kingly head
He to a learned clerk beside him said,
“What mean these words?” The clerk made answer meet,
“He has put down the mighty from their seat,
And has exalted them of low degree.”
Thereat King Robert muttered scornfully,
“’T is well that such seditious words are sung
Only by priests and in the Latin tongue;
For unto priests and people be it known,
There is no power can push me from my throne!”
And leaning back, he yawned and fell asleep,
Lulled by the chant monotonous and deep.

When he awoke, it was already night;
The church was empty, and there was no light,
Save where the lamps, that glimmered few and faint,
Lighted a little space before some saint.
He started from his seat and gazed around,
But saw no living thing and heard no sound.
He groped towards the door, but it was locked;
He cried aloud, and listened, and then knocked,
And uttered awful threatenings and complaints,
And imprecations upon men and saints.
The sounds re-echoed from the roof and walls
As if dead priests were laughing in their stalls.

At length the sexton, hearing from without
The tumult of the knocking and the shout,
And thinking thieves were in the house of prayer,
Came with his lantern, asking, “Who is there?”
Half choked with rage, King Robert fiercely said,
“Open: ’tis I, the King! Art thou afraid?”
The frightened sexton, muttering, with a curse,
“This is some drunken vagabond, or worse!”
Turned the great key and flung the portal wide;
A man rushed by him at a single stride,
Haggard, half naked, without hat or cloak,
Who neither turned, nor looked at him, nor spoke,
But leaped into the blackness of the night,
And vanished like a spectre from his sight.

Robert of Sicily, brother of Pope Urbane
And Valmond, Emperor of Allemaine,
Despoiled of his magnificent attire,
Bareheaded, breathless, and besprent with mire,
With sense of wrong and outrage desperate,
Strode on and thundered at the palace gate;
Rushed through the courtyard, thrusting in his rage
To right and left each seneschal and page,
And hurried up the broad and sounding stair,
His white face ghastly in the torches’ glare.
From hall to hall he passed with breathless speed;
Voices and cries he heard, but did not heed,
Until at last he reached the banquet-room,
Blazing with light and breathing with perfume.

There on the dais sat another king,
Wearing his robes, his crown, his signet-ring,
King Robert’s self in features, form, and height,
But all transfigured with angelic light!
It was an Angel; and his presence there
With a divine effulgence filled the air,
An exaltation, piercing the disguise,
Though none the hidden Angel recognize.

A moment speechless, motionless, amazed,
The throneless monarch on the Angel gazed,
Who met his look of anger and surprise
With the divine compassion of his eyes;
Then said, “Who art thou? and why com’st thou here?”
To which King Robert answered, with a sneer,
“I am the King, and come to claim my own
From an impostor, who usurps my throne!”
And suddenly, at these audacious words,
Up sprang the angry guests, and drew their swords;
The Angel answered, with unruffled brow,
“Nay, not the King, but the King’s Jester, thou
Henceforth shall wear the bells and scalloped cape,
And for thy counsellor shalt lead an ape;
Thou shalt obey my servants when they call,
And wait upon my henchmen in the hall!”

Deaf to King Robert’s threats and cries and prayers,
They thrust him from the hall and down the stairs;
A group of tittering pages ran before,
And as they opened wide the folding door,
His heart failed, for he heard, with strange alarms,
The boisterous laughter of the men-at-arms,
And all the vaulted chamber roar and ring
With the mock plaudits of “Long live the King!”

Next morning, waking with the day’s first beam,
He said within himself, “It was a dream!”
But the straw rustled as he turned his head,
There were the cap and bells beside his bed,
Around him rose the bare, discolored walls,
Close by, the steeds were champing in their stalls,
And in the corner, a revolting shape,
Shivering and chattering sat the wretched ape.
It was no dream; the world he loved so much
Had turned to dust and ashes at his touch!

Days came and went; and now returned again
To Sicily the old Saturnian reign;
Under the Angel’s governance benign
The happy island danced with corn and wine,
And deep within the mountain’s burning breast
Enceladus, the giant, was at rest.

Meanwhile King Robert yielded to his fate,
Sullen and silent and disconsolate.
Dressed in the motley garb that Jesters wear,
With look bewildered and a vacant stare,
Close shaven above the ears, as monks are shorn,
By courtiers mocked, by pages laughed to scorn,
His only friend the ape, his only food
What others left,–he still was unsubdued.
And when the Angel met him on his way,
And half in earnest, half in jest, would say
Sternly, though tenderly, that he might feel
The velvet scabbard held a sword of steel,
“Art thou the King?” the passion of his woe
Burst from him in resistless overflow,
And, lifting high his forehead, he would fling
The haughty answer back, “I am, I am the King!”

Almost three years were ended; when there came
Ambassadors of great repute and name
From Valmond, Emperor of Allemaine,
Unto King Robert, saying that Pope Urbane
By letter summoned them forthwith to come
On Holy Thursday to his city of Rome.
The Angel with great joy received his guests,
And gave them presents of embroidered vests,
And velvet mantles with rich ermine lined,
And rings and jewels of the rarest kind.
Then he departed with them o’er the sea
Into the lovely land of Italy,
Whose loveliness was more resplendent made
By the mere passing of that cavalcade,
With plumes, and cloaks, and housings, and the stir
Of jewelled bridle and of golden spur.
And lo! among the menials, in mock state,
Upon a piebald steed, with shambling gait,
His cloak of fox-tails flapping in the wind,
The solemn ape demurely perched behind,
King Robert rode, making huge merriment
In all the country towns through which they went.

The Pope received them with great pomp and blare
Of bannered trumpets, on Saint Peter’s square,
Giving his benediction and embrace,
Fervent, and full of apostolic grace.
While with congratulations and with prayers
He entertained the Angel unawares,
Robert, the Jester, bursting through the crowd,
Into their presence rushed, and cried aloud,
“I am the King! Look, and behold in me
Robert, your brother, King of Sicily!
This man, who wears my semblance to your eyes,
Is an impostor in a king’s disguise.
Do you not know me? does no voice within
Answer my cry, and say we are akin?”
The Pope in silence, but with troubled mien,
Gazed at the Angel’s countenance serene;
The Emperor, laughing, said, “It is strange sport
To keep a mad man for thy Fool at court!”
And the poor, baffled Jester in disgrace
Was hustled back among the populace.

In solemn state the Holy Week went by,
And Easter Sunday gleamed upon the sky;
The presence of the Angel, with its light,
Before the sun rose, made the city bright,
And with new fervor filled the hearts of men,
Who felt that Christ indeed had risen again.
Even the Jester, on his bed of straw,
With haggard eyes the unwonted splendor saw,
He felt within a power unfelt before,
And, kneeling humbly on his chamber floor,
He heard the rushing garments of the Lord
Sweep through the silent air, ascending heavenward.

And now the visit ending, and once more
Valmond returning to the Danube’s shore,
Homeward the Angel journeyed, and again
The land was made resplendent with his train,
Flashing along the towns of Italy
Unto Salerno, and from thence by sea.
And when once more within Palermo’s wall,
And, seated on the throne in his great hall,
He heard the Angelus from convent towers,
As if the better world conversed with ours,
He beckoned to King Robert to draw nigher,
And with a gesture bade the rest retire;
And when they were alone, the Angel said,
“Art thou the King?” Then, bowing down his head,
King Robert crossed both hands upon his breast,
And meekly answered him: “Thou knowest best!
My sins as scarlet are; let me go hence,
And in some cloister’s school of penitence,
Across those stones, that pave the way to heaven,
Walk barefoot, till my guilty soul be shriven!”

The Angel smiled, and from his radiant face
A holy light illumined all the place,
And through the open window, loud and clear,
They heard the monks chant in the chapel near,
Above the stir and tumult of the street:
“He has put down the mighty from their seat,
And has exalted them of low degree!”
And through the chant a second melody
Rose like the throbbing of a single string:
“I am an Angel, and thou art the King!”

King Robert, who was standing near the throne,
Lifted his eyes, and lo! he was alone!
But all apparelled as in days of old,
With ermined mantle and with cloth of gold;
And when his courtiers came, they found him there
Kneeling upon the floor, absorbed in, silent prayer.

Tales of a Wayside Inn by Henry Wadsworth Longfellow, Part First, The Sicilian’s Tale: King Robert of Sicily

Source text taken from: https://en.wikisource.org/wiki/Tales_of_a_Wayside_Inn/Part_First/The_Sicilian%27s_Tale/King_Robert_of_Sicily