Reversed half H
The reversed half H (Ꟶ or ꟶ) was an epigraphic letter used in Latin inscriptions from Roman Gaul. In French epigraphy works, it is called , "halved H". History 

It is derived from the right part of . It represents the aspirate h or rough breathing. It is found at the beginning of words, and following , , and , in words which have an original Greek  (),  () or  (). It may or not be related to the characters  and  used by Aristophanes of Byzantium to represent the rough breathing and smooth breathing of Greek around 200 BC. The half H is found in Latin inscriptions of Gaul, particularly the areas of Lugdunum (Lyon) and Nemausus (Nîmes) in modern France. Of the variant forms of H found in inscriptions, the reversed half H is the only one commonly distinguished from the ordinary H in diplomatic transcriptions. A few authors have considered the reversed half H to be a ligature of H with the preceding letter, but  and catalogues of local inscriptions treat the reversed half H as a distinct letter. There are cases of clear , , , ,  ligatures but, in others, there is visible space between  and the previous and following letter. Unicode 
The letter was introduced in Unicode 13 (March 2020). While the inscriptions show only uppercase forms, a lowercase version has also been entered into Unicode to allow epigraphists to discuss words in appropriate cases. It is named "reversed" to distinguish it from the previously encoded Claudian letter half H . See also 

 Claudian letter 
 Heta ()

References

Works cited 
 

Gallo-Roman culture
Epigraphic letter variants