The People of Gibraltar
1779 - Queen of Spain’s Chair - Gibraltar - Isabelline 

Watch tower - perhaps of Arabic origin - on the summit of Sierra Carbonera to the north of the Spanish town of La Línea - It was known colloquially by the British as "The Queen of Spain's Chair"   (1906)

But let me start with a quote from Mark Twain’s The Innocents Abroad:
We had no sooner gotten rid of Spain distress than the Gibraltar guides started another - a tiresome repetition of a legend that had nothing very astonishing about it even in the first place; "that high hill yonder is called the Queen of Spain's Chair; it is because one of the Queens of Spain placed her chair there when French and Spanish troops were besieging Gibraltar, and said she would never move from the spot until the English flag was lowered from the fortress. If the English hadn't been gallant enough to lower the flag for a few hours one day, she'd have had to break her oath or die up there"

Mark Twain and Guide and a wrongly shaped Sierra Carbonera       (1869 - The Innocents Abroad)      (See LINK)

Also the explanation given by one of the editors of Mark Twain’s Papers and Journals (1855-1873):
It was commonly believed without any basis in fact, that the queen of Spain sat in the tower at the summit of Sierra Carbonera during the Great Siege of Gibraltar (1779-1783), refusing to leave until the British flag was lowered. Out of compassion for the queen General George Augustus Eliott governor of Gibraltar and commander of the British troops there, was said to have lowered the flag so that she might depart with honour. Clemens (Mark Twain) makes the yarn, if possible, even more tiresome in Chapter 7 of The Innocents Abroad.

 General George Augustus Eliott       (A. Poggi)

Alonso Hernández del Portillo (see LINK) the author of the Historia de la Muy Noble y Muy Leal Ciudad de Gibraltar which was written in the early 17th century is possibly the first historian to mention the tower at the top of Sierra Carbonera. He thought it had been built either by either the Carthaginians or the Romans. There is no mention of any Queen - Spanish or otherwise.

Oldest extant pictorial representation of the tower on the summit of Sierra Carbonera  ( (1567 - Anton Wyngaerde)

Nor can I find any English reference to the myth of “the Queen of Spain’s Chair” before the early 19th century. It appears in the Gentleman’s Magazine in an article on Gibraltar written by an anonymous correspondent who visited the Rock in 1802. The author’s description is identical to that given above by the editor of Mark Twain’s papers.

Surprisingly the story did not catch on until several decades later. Writing in 1809 Sir John Galt, for example, (see LINK)  gives us the following:
The mountains of Andalusia are seen rising at a distance, beyond the hill which has been called the Queen's seat ever since it was the station from which the infamous Queen of Spain surveyed the grand attack on the fortress, and witnessed the destruction of the floating batteries.
In other words she was up there during the Great Siege of Gibraltar and - according to Galt -- specifically on the September 13th 1782. Unfortunately he fails to explain the myth and attributes the name to the entire Sierra rather than to any particular tower.

Sierra Carbonera looms top right (1785 - Roberts)    (See LINK)

Detail of the Sierra from another engraving by Roberts - the masts on the tower suggest a very similar construction to that of the Signal Station at the top of the Rock at the time  

Galt’s contemporary, Sir John Carr (see LINK) was less specific. 
. . . the hill (Sierra Carbonera) from whence the Queen of Spain contemplated as a spectacle the memorable siege of Gibraltar

Detail from an engraving of the Great Siege - the artist has made sure that the Queen of Spain’s Chair - background right - forms part of the scene    (John Singleton Copley) (See LINK

An 1840s edition of The Shores and Islands of the Mediterranean (see LINK) includes an engraving - shown below in colour - of the view from a ruined lower tower on the foothills of the Sierra. It was known by the Spanish as Torre las Pedreras.

“From the lower signal-tower at the foot of the Queen of Spain’s Chair” - These were the ruins of a second tower     (1839 - H.E. Allen)  (See LINK)

Shores and Islands also includes the following slightly over the top description yet more believable reason for the name of the tower:
During the memorable siege of Gibraltar, the Queen of Spain commanded a tower to be erected, from which, like another Helen, she might view the warrior-train, and witness the humiliation of her enemies. Such a consummation, however, she was not destined to behold; and the ruins of the tower, now called “The Queen of Spain's Chair,” are emblematic of the fortunes of the fleets and the armies that were destroyed in her presence.

View from the lower signal tower - Queen of Spain’s Chair    (1839 - H.E. Allen)  (See LINK)

An article in an 1855 edition of the Ladies Companion and Monthly Magazine by an anonymous Naval Chaplain dwells on every conventional detail he can extract from the story and ends with “Se non e vero, e ben trovato . . . "

That the entire story behind the Queen of Spain's Chair is a myth seem quite evident to me but I have yet to find out who was originally responsible or even approximately when the name came into existence. My underlying gut feeling is that this was a bit of British propaganda designed to ridicule Spain during the Great Siege while at the same time depicting Eliott as a gallant gentleman. Unfortunately there are several reasons why this does not ring true. 

For a start the Great Siege took place during the reign of King Charles III of Spain who was 67 years old by the time hostilities ended. His wife the queen consort Maria Amelia of Saxony died in 1760 and Charles III as far as I can make out never remarried.  So whoever is supposed to have sat on that “chair” during the Siege it can’t have been Maria Amelia or any other Spanish Queen. Nor could Eliott have been involved in any way. 

Maria Amalia of Saxony - I doubt whether she ever sat on the Queen of Spain’s Chair

The earliest mention of the phrase “the Queen of Spain’s Chair” is in John Drinkwater’s definitive history of the Great Siege published in 1789. (See LINK) Although he uses the phrase at least seven times he does not offer any reason as to why the place was given that name. From this I deduce that it was already in common usage by 1779. If it had been created during the Siege it seems inconceivable that Drinkwater - a man who hero worshipped Eliott and tended to despise anything Spanish would not have taken the trouble to tell us.

Nevertheless if the origin of the phrase is British then it must have been created after 1704 the year in which Gibraltar was captured by Anglo-Dutch forces as a consequence of the War of the Spanish Succession. (See LINK) They did so in the name of the pretender to the Spanish throne Charles Archduke of Austria. This conflict - the 11th Siege of Gibraltar - was followed almost immediately by an attempt by the Spanish to recover the place - the 12th Siege of Gibraltar which ended in 1705.

More of a curiosity than anything else, a footnote in the Journals of George Rooke suggests that Rooke’s co-commander during the assault on Gibraltar in 1704 - Prince George of Hesse-Darmstadt - was “warmly” attached to the widow of Charles II - Maria Anna of Neuburg - Queen of Spain from 1689 to 1700. Could she have been the “Queen”? I very much doubt it.

Maria Anna of Neuburg - almost certainly never sat on the Queen of Spain’s chair either

The man actually occupying the throne in Madrid during the 12th and 13th Sieges was the French Bourbon candidate - Philip V of Spain. His wife in 1704 was the queen consort Maria Luisa of Savoy who was 16 years old in 1704. 

Maria Luisa of Savoy

Philip, described by some as a religious fanatic and a feeble-minded nymphomaniac - was very much under Maria Luisa’s very young thumb. I have never read a biography of her but it seems unlikely that Maria Luisa - who was no feeble-minded bimbo herself - would have dragged herself down south to oversee what was patently a very unsuccessful campaign. Besides she was looking after the store for Philip while he was elsewhere fighting his own right to succeed the throne of Spain. 

The next and last conflict between Britain and Spain involving the Rock was the 13th Siege. It took place in 1727. Spain was still ruled by Philip V who had remarried in 1714. His wife was Elisabeth Farnese - Isabel de Farnesio in Spanish. A woman of some character she took advantage of her husband many shortcomings and eventually became the de facto ruler of Spain.

Isabel de Farnesio

In theory “Isabel” should be a good candidate for the “Queen” in the Queen’s chair.  Philip had always been keen on getting Gibraltar back from Britain and - as George Hills explains in his Rock of Contention - “Elizabeth . . . made Philip’s passion for Gibraltar her own”.

Whether the naming of the tower was a metaphor for the queen who may have been held responsible by the British for this particular siege I have no idea.  But history makes no mention of Elizabeth Farnese ever having visited the Spanish lines. Beside it would have been completely out of character for a person as savvy as “Isabel” to have placed herself so open to ridicule. 

But let me go back a few years to 1601 when the Archduke Albert VII of Austria commander of a large Spanish army, lay siege to the Flanders’s port of Ostend.

Albert VII of Austria’s portrait by Paul Rubens

The Siege was part of a lengthy and continuing conflict between Catholic Spain - at the time rulers of Belgium - and the Protestant Dutch to the north. The story goes that Albert’s wife - Isabella Clara Eugenia - believing that the siege would be very short lived, vowed that she would neither change nor wash her underwear until the Archduke had won. In the event the Siege lasted more than three years and earned itself the record of the most lethal in history. 100 000 people died during the conflict.

Isabella Clara Eugenia - presumably with well washed underwear

I am almost certain that this one is also a “myth” but it does allow one to speculate. The Siege of Ostend was probably even more famous in Europe than Gibraltar’s very own Great Siege. Also there were a considerable number of Dutch soldiers involved in the 1704 capture of Gibraltar and the subsequent Siege and it seems reasonable to suppose that many of them would have been well aware of their ancestors’ exploits a century previously.

More pertinently they may also have heard the story of Isabella Clara Eugenia and it might just be possible that one of them may have been responsible for starting an equivalent story intended to belittle the enemy and while away the time.

Yet another possibility is that that the phrase was coined as far back as the 14th century during the 5th Siege of Gibraltar. In 1333 the Spanish King Alfonso XI encamped on the isthmus as he besieged Gibraltar which was held by Arab forces. More to the point Alfonso had brought his mistress Eleanor of Guzman and his ten illegitimate children with him.
The legend goes that Eleanor watched proceedings from her vantage point near the tower at the top of the Sierra - hence la Silla de la Reina - despite the fact that Eleanor was not a Queen but the King’s mistress. There is evidence that she was present in the area during the siege but it is highly unlikely that she would have left the security of the Kings camp to wander about in what was a dangerous countryside in those days.

Nevertheless it undoubtedly qualifies as a possible source for the British version - simply a different queen and a different siege.

Soon after Alfonso XI died, Eleanor de Guzman was imprisoned and sentenced to death by the King’s wife Maria de Portugal - In this paining she is bidding her son farewell in the presence of the Queen

In the final analysis, I suspect that nobody has a clue as to why the tower that once stood on the top of Sierra Carbonera came to be known as “The Queen of Spain’s Chair”. What I did find out while researching this article is that there is a shade of white known in the trade as “Isabelline”. Some have suggested that this is a reference to the colour of Isabella Clara’s shift after wearing the thing for more than three years.