Page 206. " it has to be the Resistance - but are they magicians or not? "

The Resistance is introduced but it is not developed in the plot; the intrigue behind a group of commoners innately resilient to magic, who mount a Resistance against the government,  is a seed planted for another book, another story.

 

Page 215. " They were two sizable utukku, stolidly marching "

Statue of the Assyrian demon Pazuzu.
Creative Commons Attribution Share AlikeStatue of the Assyrian demon Pazuzu. - Credit: PHGCOM
According to Bartimaeus, the Utukku are type of djinni known for its unintelligent devotion to violence; they were favoured by the Assyrians. Xerxes (aka Eagle-beak) appearance might be based upon some Assyrian demon like Pazuzu, for example, who is often depicted as a combination of diverse animal and human parts.

 

Page 215. " I first fought these at the battle of Al-Arish "

Arish (or el-Arish) is a town in north eastern Egypt, in the Sinai peninsula, on the Mediterranean Sea. The city grew around a Bedouin settlement near the ancient Egyptian Ptolemaic Dynasty outpost of Rhinocolura. According to Bartomaeus, Al-Arish was the  site of an ancient battle between Assyrian and Egyptians.

 

Page 217. " We're in the Tower. The Tower of London. "

Tower of London, The White Tower
Creative Commons Attribution Share AlikeTower of London, The White Tower - Credit: Robert Swinney
Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically as The Tower), is a historic fortress in central London, on the north bank of the River Thames. The Tower of London is often identified with the White Tower, the original stark square fortress built by William the Conqueror in 1078. However, the tower as a whole is a complex of several buildings set within two concentric rings of defensive walls and moat.

The tower's primary function was a fortress, a royal palace, and a prison (particularly for high status and royal prisoners, such as the future Queen Elizabeth I. This last use has led to the phrase "sent to the Tower" (meaning "imprisoned"). It has also served as a place of execution and torture, an armoury, a treasury, a zoo, the Royal Mint, a public records office, an observatory, and since 1303, the home of the Crown Jewels of the United Kingdom.

 

Page 220. " perished in the Thirty Years War. "

Model of a Pike and shot  formation from the Thirty Years' War.
Public DomainModel of a Pike and shot formation from the Thirty Years' War. - Credit: Peter Isotalo
The Thirty Years' War (1618–1648) was one of the most destructive conflicts in European history. The war was fought primarily (though not exclusively) in what is now Germany and at various points involved most of the countries of Europe. Naval warfare also reached overseas and shaped the colonial formation of future nations.

The origins of the conflict and goals of the participants were complex and no single cause can accurately be described as the main reason for the fighting. A major impact of the Thirty Years' War was the extensive destruction of entire regions, denuded by the foraging armies. Episodes of famine and disease significantly decreased the populace of the German states, Bohemia, the Low Countries and Italy, while bankrupting most of the combatant powers. Some of the quarrels that provoked the war went unresolved for a much longer time. The Thirty Years' War was ended with the treaties of Osnabrück and Münster, part of the wider Peace of Westphalia.