The Mirror of Erised | Wizarding World https://www.wizardingworld.com/writing-by-jk-rowling/the-mirror-of-erised
The Mirror of Erised is a very old device. Nobody knows who created it, or how it came to be at Hogwarts School. A succession of teachers have brought back interesting artefacts from their travels, so it might have arrived at the castle in this casual manner, either because the teacher knew how it worked and was intrigued by it, or because they did not understand it and wished to ask their colleagues’ opinions.
The mirror’s inscription (‘erised stra ehru oyt ube