Corporations are often traced back to ancient Rome (i.e. "Roman Colleges") (or even "municipal communes"). It might be that where corporations are prevalent, attorneys must necessarily be. "Priesthood" of managing the bridge between the living and the dead. To be quite frank, a study of corporations could very much potentially cross over into the topic of egregores, black magic and necromancy.
Fortunately its easy to study the history of corporate law via free online books such as this one: Business Organization and Combination (from 1921) (link direct to page that starts a detailed historical sketch).
Related (refers to corporations and New York City):