出典:Wiktionary
From Proto-Italic *sekʷōr, from Proto-Indo-European *sekʷ- (“to follow”). Cognates include Sanskrit सचते (sácate), Avestan (hacaitē) and Ancient Greek ἕπομαι (hépomai).
sequor (present infinitive sequī, perfect active secūtus sum); third conjugation, deponent
The verb ducere is used for "to be followed," effectively giving ducere two passives, this verb being one of them.
In later Latin, an active voice was invented for "to follow," leading to the passive forms being relegated to "to be followed."