Question: Who is the {praetorian prefecture} for {located in the administrative territorial entity} of {Roman Empire}
Paraphrase: Who is the {praetorian prefecture} for {found within the regulatory regional substance} of {Roman Empire}
SPARQL (Wikidata):  select distinct ?sbj where { ?sbj wdt:P131 wd:Q2277 . ?sbj wdt:P31 wd:Q4377540 } 
Answer: praetorian prefecture of Gaul