Origins
Control started as paperwork. Medieval Latin contrārotulāre meant 'to check a record against its duplicate scroll' — a counter-roll, used to prevent fraud in royal and ecclesiastical accounting. A controller was a clerk who verified the books. Power had nothing to do with it.
The word entered English through Anglo-French contreroller in the 14th century, still meaning 'to check' or 'to verify'. The title comptroller — still used for senior financial officers in governments worldwide — preserves this original bookkeeping sense, complete with its archaic spelling.
Modern Usage
The shift from verification to domination happened in stages. To check something is to monitor it. To monitor it regularly is to regulate it. To regulate it absolutely is to control it. By the 16th century, control had acquired its modern sense of power over people and events.
The rotulus element means 'a small wheel' or 'a roll of parchment'. It also gives English the words role (originally a roll of parchment listing an actor's lines), roll, and enrol (to write on a roll). Control, role, and enrolment all trace back to the same scroll of parchment in a medieval accounting office.