A fabric is used for a pretty silk dress,
an empire eventually broke under stress,
a language once used one's ideas to express,
a man, head of Reich long before the SS.
What am I?
A fabric is used for a pretty silk dress,
Ottoman is a silk fabric used for formal dresses.
an empire eventually broke under stress,
The Ottoman empire, from 1299 to 1923, broken by the Allied Powers in the aftermath of WWI.
a language once used one's ideas to express,
The Ottoman language, a variety of Turkish.
a man, head of Reich long before the SS.
Otto the man, one of whom was Otto I the Great, the first Holy Roman Emperor.
Title: Head of a Reich takes a seat
An ottoman is a piece of furniture in the form of a couch or stool.