Yes, I am still curious about the book.
The date on the "Daredevils" coin is AH 1277 but there is also a
"Regnal year" of 10, which is the tenth year the Ottoman Sultan
was on the job.
These are Moslem lunar years which are shorter than Western years,
about 354 days or 97%.
The coin date would be AH 1277 plus 9 (as 1277 is already year 1),
then converted to an AD date.
AD 1869 = AH 1286 x 0.97 + AD 622 (Base year for Moslem dates).
Some Moslem countries use the Moslem base year and add solar years.
This question will be on the test.