This map above shows where most of the Saxons (what many of the Germans in Transylvania were called) lived within the borders of Transylvania. It gives one a good idea of where some people lived when Transylvania was a part of Hungary. This was a time where the people of Transylvania lived within a huge empire called the Austrian Empire. For recording purposes, Transylvania was a part of the Kingdom of Hungary.
Tranyslvania and Hungary played an important part in the history of Europe. This is also true of Romania, except that Romania, as a country, was not formed until the late 1800s. Now, after the Second World War, there are many people from Tranyslvania who have migrated to Hungary and Germany. I published a book which you can buy on amazon.de and amazon.co.uk about several Transylvania Saxon soldiers, some of whom later migrated from Transylvania to new homelands.