Leather notebook of some kind

I believe this is a notebook of some kind from Lima(Peru). I also believe this is quite old. I am having trouble finding out about it, because I haven't found another on the Internet.
It measures 34cm(13 1/4in) long and 6 1/2cm(10 4/10in) wide when opened it measures 53cm(21 in) wide.
On the front it is inscribed with "HOC SIGNUM VERE REGUM EST." meaning "the true signal of the kings" in Latin.