The paenula was a cloak worn by the Romans

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

, akin to the poncho of the modern Spaniards and Spanish Americans (i.e. a large piece of material with a hole for the head to go through, hanging in ample folds round the body). This was originally worn only by slaves, soldiers and other people of low degree; in the 3rd century, however, it was adopted by fashionable people as a convenient riding or travelling cloak; and finally, by the sumptuary law of 382 (Cod. Theod.

Codex Theodosianus

The Codex Theodosianus was a compilation of the laws of the Roman Empire under the Christian emperors since 312. A commission was established by Theodosius II in 429 and the compilation was published in the eastern half of the Roman Empire in 438...

 xiv. 10, r, de habitu. intra urbem) it was prescribed as the proper everyday dress of senators, instead of the military chlamys

Chlamys

The chlamys was an ancient Greek piece of clothing, a type of cloak....

, the toga

Toga

The toga, a distinctive garment of Ancient Rome, was a cloth of perhaps 20 ft in length which was wrapped around the body and was generally worn over a tunic. The toga was made of wool, and the tunic under it often was made of linen. After the 2nd century BC, the toga was a garment worn...

being reserved for state occasions.