The Donmeh are a group of people who originally were part of the Ottoman Empire (which is now Turkey and surrounding areas). They follow a special version of Islam but have some unique beliefs and traditions.
A long time ago, during the Ottoman Empire, the rulers sometimes forced certain groups to change their religion or beliefs. The Donmeh were originally Jews who, centuries ago, converted to Islam to avoid persecution or for political reasons. However, they secretly kept some of their old Jewish traditions and beliefs inside their new Islamic practice.
So, in simple terms:
The Donmeh are people who converted from Judaism to Islam but kept some of their original beliefs hidden.
They mainly lived in parts of the Ottoman Empire, especially in what is now Turkey.
They were not forced to convert in a straightforward way; instead, they chose to convert, often under pressure or for safety, but kept their unique traditions secret.