I have no idea but my guess would be early 21st century AD.
There is nothing like them in any reference I own or have looked at regarding ancient
brooches (see my earlier
thread or my
wikipedia article on
fibula for a partial bibliography)
nor have I ever seen anything like them in a museum.
The pin is extremely thick compared to most genuine surviving pins that you see and the simple flat
pin catch placed perpendicular to the pin is a hallmark of recent
Bulgarian fakes.
Shawn