Não, eles existiram em outro lugar ao mesmo tempo
Livro dos Feitiços é um livro de duzentos anos que descreve uma "história antiga" sobre Dementadores.
The strange power of the Patronus, and its peculiar qualities, are well illustrated by the ancient story of a shy, poor orphan boy called Illyius, whose Patronus went down in wizarding history.
Illyius lived long ago in a mountain village, which was surrounded by a dense forest in which a Dark wizard called Raczidian lived in a black castle guarded by Dementors. These evil, faceless, hooded creatures, which cast fear and despondency all around them, such the very souls from humans whom they succeed in For many years, Raczidian left the villagers, who were fellow witches and wizards, in peace, and they avoided the part of the forest where his castle was situated. Knowing that Dementors roamed the forest, they took care to teach every new generation the Patronus Charm, the only spell that worked against these evil creatures. Many were unable to master the difficult spell, but there had always been just enough Patronuses in the village to stand guard against the Dementors, in case Raczidian ordered an attack.
(Wonderbook: Book of Spells - Chapter 5)
Além disso, sabemos que o Feitiço Patrono já existe há mais tempo (embora isso tenha outros usos).
It is clear from ancient woodcuts and scrolls that the Patronus Charm has been in existence since earliest times. Many attempts have been made over the centuries to find an easier way to produce a Patronus, or some similar shield against Dark magic, but none have been successful. If you seek the best protection magic can afford against evil creatures, your only choice is to perfect the Patronus Charm.
(Wonderbook: Book of Spells - Chapter 5)