An anachronistic flying machine.

There is a vast anachronism as early as the second episode of The Bureau of Magical Things. I hate anachronisms.

The second episode "Magic in the Air", October 9, 2018, featured a flying chair as the magical threat. A flying chair doesn't seem so menacing, but elves and fairies and other magical people in this series seem very paranoid about humans discovering that magic exists, believing it will cause disaster for them and for humans, so the flying chair has to be caught before it comes to the attention of humans in general.

The chair is described as the Flying Throne of Kay Kavus. Kay Kayus, or Kai-Kaus, was a mythical, legendary, or possibly semi historical more or less Iranian King.

Kay Kavus was supposedly the son of Kay Qobad and the father of Prince Seyavash, the father of his successor Kai Khosraw.

Professor Maxwell says that Kay Kavus ruled in the First Millennium. When people say just plain "The First Millennium" they usually mean the First Millennium AD (AD 1 to AD 1000). It is possible that the reign of the fictional or possibly real Kay Kavus could be dated to the First Millennium BC (1000 BC to 1 BC), but it might date back to the Second Millennium BC (2000 BC to 1001 BC).

Kay Kavus was a member of the Kayanian dynasty which ruled (if not totally fictional) sometime before the First Persian Empire of the Achaemenid dynasty, and the Achaemenid dynasty ruled the First Persian Empire from about 550 BC to 330 BC.

According to some stories the reign of Kay Kavus, who supposedly ruled for 150 years, was contemporary with the reign of King Solomon of Israel, who supposedly reigned from about 970 BC to about 931 BC. Thus it would be possible that the real or imaginary reign of Kay Kavus would be in the First Millennium BC (1000 BC to 1 BC), though it would also be possible that the reign of Kay Kavus might have begun in the Second Millennium BC (2000 BC to 1001 BC).

But another account makes Kay Khosrow contemporary with the prophet Zoroaster.

There is no scholarly consensus on when he lived.[11] However, approximating using linguistic and socio-cultural evidence allows for dating to somewhere in the second millennium BCE. This is done by estimating the period in which the Old Avestan language (as well as the earlier Proto-Indo-Iranian and Proto-Iranian languages and the related Vedic Sanskrit) were spoken, the period in which the Proto-Indo-Iranian religion was practiced, and correlation between the burial practice described in the Gathas with the archeological Yaz culture. However, other scholars still date him in the 7th and 6th century BCE as a near-contemporary of Cyrus the Great and Darius I.[12][2][13][14][15]