Too Many Magicians is the only Lord Darcy novel written by Randall Garrett: it first appeared in Analog magazine from August to November 1966 and was issued in book form by Doubleday in 1967.
[2] Magic is a scientific discipline, codified in the fourteenth century by Saint Hilary Robert, much involved with higher mathematics and possessed of theoretical and experimental underpinnings as sophisticated as those of real world physics and chemistry.
The characters all live in the Anglo-French domain, but include a Polish refugee, who was accused by the Italian government of black magic and is compelled to spy for Poland by a threat to her uncle.
Characters travel by horse-drawn carriage and steam train and employ revolving pistols and bolt-action rifles; buildings are illuminated with gas lights.
Medical technology is not as advanced as in the real world, because Healers are so effective, indeed the use of drugs with a genuine but non-magical benefit ("may cover a wound with moldy bread... or give a patient with heart trouble a tea brewed of foxglove") is regarded as little more than superstition.
Richard I returned to England after he was wounded at the siege of Chaluz, but he later recovered and ruled well, but John Lackland never held the throne and died in exile.
Richard dethroned the Capetian Dynasty and made himself and his successors Kings of France as well as of England, both kingdoms being ruled from London, while Paris was left into the 20th century a provincial town that broods over its lost glory.
Ireland seems to have been spared traumatic periods of foreign colonisation and dispossession, and since everybody is Catholic, it has no problems of rival religious-ethnic communities.
The chronologically-first but not the first-written Lord Darcy story takes place during a military confrontation between Anglo-French and Polish forces on the soil of Bavaria.
Italy being united implies that the Catholic Church was, like in real world history, deprived at some time of its Temporal power over the city of Rome and its environs, but there is no mention of when and how that happened.
Poland is a major power and the chief rival of the Anglo-French, and both exist in a situation of Cold War; some of the stories are spy thrillers in which Lord Darcy is pitted against Polish agents and takes on some of the attributes of James Bond (with some magic ingredients added, such as a spell used to make him fall madly in love with a beautiful female Polish agent).
Hungary is part of the Polish Empire (the University of Buda-Pest is mentioned as one of Poland's major institutes of learning), which seems to extend southwards into the Balkans.
The Russias are no more than a set of fractious statelets, which might unify in the face of Polish aggression but as yet have failed to do so (it had been close to that situation in some periods of real world history, as during the Polish-Muscovite War (1605–1618)).
As noted, the Byzantine Empire continues to exist and is, at least at times, an Anglo-French ally, but it is a minor power corresponding to real world Greece, with its main importance being the control of the strategic Dardanelles.
Also, with John Lackland never taking the throne, he never had a chance to behave tyrannically as a king and so there was no rebellion culminating in the Magna Carta, which may very partially explain the lack of any democratic institutions in this 20th century.
Mexico (Mechicoe in Anglo-French) is still ruled by Aztecs, who are headed by the Christianised descendants of Montezuma after they have been taken into the empire's high nobility and possess considerable autonomy.
Lord Darcy's father, who was an army "coronel" (colonel), is mentioned as having fought in a war at Sudan, which might be not exactly the same as the real world timeline's state of that name.
In West Africa, black states are mentioned as maintaining their independence, keeping a balance between the Anglo-French and the Poles and possessing enough technology to equip modern warships.