In the summer of 1809, Britain and Spain had been allies against France for just over a year. Sir Arthur Wellesley was currently in the Iberian Peninsula with an army of about 30,000 men. Diplomatic relations with Spain, however, remained a little fraught – the two countries had been at war for much of the last decade, memories of Trafalgar were still fresh, and there was the little outstanding matter of Gibraltar, which made the prospect of any large body of British troops on Spanish soil a bit difficult.
Understandably, therefore, the Spanish decided it was time to offer an olive branch in the form of a gift to His Majesty King George III. Their ambassador, Don Pedro de Cevallos, arrived in London in February 1809, bringing the King the Collar of the Order of the Golden Fleece. 
This the King refused, as it was his policy not to accept Orders from foreign governments (he felt it was improper for him to do so as the head of the Orders of his own kingdom). The Spanish, however, still wanted to make a statement of their gratitude for the way the Brits were helping them eject the French invaders from their country. They decided to think laterally, although they still kept to the fleecy theme.
Their thoughtful gift was an unspecified number of very valuable Merino sheep, much prized (then as now) for the quality of their wool, and this George III did accept.
Delighted by the success of their diplomatic coup, the Spanish decided to send him another gift. What do you get the King who’s got everything? Apparently, you get him more sheep, as a letter to the King from the Foreign Secretary, George Canning, dated 2 June 1809, makes clear:
“Mr Canning most humbly requests Your Majesty’s gracious Commands as to the answer to be returned to the Offer, by the Supreme Junta, of 4,000 Merino Sheep as a Present to Your Majesty.”
The King was very grateful, but the problem was he didn’t want any more sheep:
“The King desires Mr Canning will assure Don Pedro Cevallos that he is very sensible of the Attention of the Supreme Junta in offering a present of 4,000 Sheep, but that His Majesty has already so large a Stock as not to require further Supply for the Accommodation of which He has not indeed the Means of providing.”
It seems the Spanish were so keen to send the sheep that they hadn’t thought about how to transport them. The transports they had sent last time had been “improperly crowded”. When the Spanish suggested the world’s foremost maritime power could just send more ships, the King pointed out that such “Ships must be sent which are required for other pressing Services.”
“Other services” referred to the expedition to Walcheren, currently taking up all the spare time, ships, and transports belonging to the Admiralty, which was having a hard enough time making up the full complement of over 650 vessels for the campaign.
The Spanish were undeterred. Would the King like some lovely Spanish horses instead?
“Upon the same Grounds the King thinks it would be advisable to decline equally the Offer of the Horses, at this moment.”
Canning duly passed on the King’s message to Cevallos; and there the matter rested.
For ten days.
On 13 June 1809, as Canning reported to the King, Cevallos — who had clearly been instructed not to take no for an answer — tried again. Maybe not 4,000 sheep then: how about a smaller number?
“Mr Canning … humbly requests to receive Your Majesty’s gracious Commands, whether he may encourage Don Pedro Cevallos to hope that Your Majesty at some future time might be graciously pleased to accept a limited number of Merino Sheep; and also a few of the Horses, when the means of transport can be conveniently afforded.”
Apparently the Spanish insisted (“No, really, please — take our sheep”).
Maybe they thought George III was just being coy. The King, however, was adamant:
“The King desires Mr Canning will persist in declining the Offer of the Merino Sheep conveyed in Don Pedro Cevallos’s note, His Majesty really not having Room for them & being actually under the Necessity of hiring Ground for those last received.”
One imagines the corridors and State Rooms at the Queen’s House full of roaming sheep, chewing on the furniture and making a tremendous mess.
The horses, however, were not positively declined:
“In regard to the horses, Don Pedro Cevallos may be told that, at a future more convenient Opportunity His Majesty will accept a few.”
This was a mistake, as the Spanish seem to have interpreted it rather more broadly than the King presumably intended. It’s possible they genuinely couldn’t believe George didn’t actually want any more sheep.
So they decided he was just being polite, and sent them anyway.
On 18 July 1809, as the preparations for Walcheren were really hotting up, a large, smelly, and very noisy package arrived in Portsmouth.
Canning was horrified:
“Mr Canning humbly reports to Your Majesty the intelligence received this day from the Admiralty of the arrival at Portsmouth of 1,500 Merino Sheep part of the present destined for Your Majesty by the Supreme Junta; which had been embarked before Your Majesty’s desire to decline that present was made known in Spain.”
Who was responsible for the mix-up? Canning didn’t know, but he did haste to assure the King he had given instructions, probably at a very high volume, to make sure such a mistake did not happen again:
“Mr Canning trusts that the notification has arrived there in time to prevent any further embarkation.”
The King’s reaction can best be summarised as “WHAT THE HELL ARE THESE QUADRUPEDS DOING HERE”:
“His Majesty is much embarrassed by the arrival of the Sheep from Cadiz, as He has not any Ground at present for them, and cannot make any Arrangements for bringing them up by Hand. The King therefore desires that Mr Canning will communicate to the Admiralty His wish that the Sheep should be sent from Portsmouth by Sea, up the River to Deptford, as the Transports will not be immediately required, the Embarkations being completed, and in the mean time His Majesty will endeavour to provide for their Disposal in those.”
(Soooo … who knew the embarkation of the Walcheren expedition was in fact delayed by the need to move 1,500 unwanted merino sheep from Portsmouth to Deptford?)
The King’s secretary, Colonel Taylor, wrote to Canning to confirm final arrangements:
“My Dear Canning, The King having ordered the Bearer Mr Smart to make arrangements for landing the Sheep at Deptford &c I trouble you with this Letter at his Desire to request You will have the goodness to furnish him with the necessary authority if he should have occasion to apply to you.”
Canning must have been extremely relieved to be able to make the sheep Someone Else’s Problem. The King’s letter is endorsed:
“Relative to Mr Smart & His Majesty’s Merino Sheep. July 20. Letter to Ld Mulgrave given to Mr Smart.”
I can just imagine Lord Mulgrave, up to his ears in Walcheren business, with the army yelling at him to provide more transports and the Transport Board yelling at him to provide more tonnage and the ships’ captains yelling at him to find out when they were supposed to be sailing, getting a visit from a gentleman smelling strongly of farmyard — said gentleman bearing a letter from the Foreign Secretary that probably said something along the lines of: “There are 1,500 sheep outside. Deal with it.”
I don’t suppose he found it very funny.
Postscript: what happened to the sheep?
I can’t be sure, although there was a letter from September 1809 referring to Spanish shepherds being placed under the control of a page in the Royal Household at the Queen’s House, so presumably some of them ended up in Green Park.
Aspinall suggests the rest of the sheep were distributed among the King’s courtiers. Canning himself didn’t get away without some (after initially declining them, but apparently his wife liked fluffy woolly ceatures more than he did, so he asked for a small flock of 50).
 Arthur Aspinall (ed.), The Later Correspondence of George III, vol. 5 (Cambridge: University Press, 1970), pp. 214-5.
 British Library Canning MSS, Add MS 89143/1/6/6, 2 June 1809. The correspondence is also printed in Aspinall.
 British Library Canning MSS, Add MS 89143/1/6/6, 3 June 1809.
 British Library Canning MSS, Add MS 89143/1/6/6, 13 June 1809.
 British Library Canning MSS, Add MS 89143/1/6/6, 14 June 1809.
 British Library Canning MSS, Add MS 89143/1/6/6, 18 July 1809.
 British Library Canning MSS, Add MS 89143/1/6/6, 19 July 1809.
 British Library Canning MSS, Add MS 89143/1/6/6, Colonel Taylor to Canning, 19 July 1809.
 Aspinall, Later Correspondence, vol. 5, p. 315 n. 1.