The Syrian Desert.
The Sahara Desert was the southern border of the roman empire
Hadrian's Wall in Britain the Danube River in Continental Europe
The western boundary of the Roman Empire was the Atlantic Sea. The eastern boundary was Persia (modern day Iran and central and southern Iraq).
The Danube River formed the northern boundary of the Byzantine Empire for much of its existence. It served as a natural barrier against invasions from various tribes and peoples in Central and Eastern Europe. The river was crucial for trade and military movements, facilitating connections between the empire and its northern territories.
The physical feature that formed the northeast boundary of Asoka's empire was the Himalayan mountain range.
The Narbada River
Sahara
At the western end of the Roman Empire there was the Strait of Gibraltar, between present day Spain and Morocco. There was not a straight at the eastern end of this empire, whose border where the Arabian desert and the Armenian Highlands. Straits in the eastern Mediterranean are the Bosporus and the Dardanelles (between European and Asian Turkey), the Strait of Rio, at the western end of the Gulf of Corinth, Greece.
The most Eastern Boundary of Rome was Constantinople which would later become the Capital of the eastern roman empire and then the Byzantiniam empire
Saharan, Nubian, Arabian.
The boundary that is formed is called a Tranform Boundary
Divergent boundary is formed