This chapter offers a brief overview of the development of the doctrine of estoppel in common law. It shows how it was initially derived from a principle of Germanic law, which barred litigants from acting inconsistently, and was latter associated with the records of the case, thus creating estoppel by record in England. The chapter also points out how the reception of the roman principle of Roman res judicata partially subverted the doctrine of estoppel—by binding its preclusive effect to the judgment rendered by a court, while it was always independent from it—and led to the distinction between estoppel and res judicata in common law. Finally, it summarizes the evolvement of estoppel through the eighteenth and nineteenth centuries, which ends in the more recognizable figure of issue preclusion (or collateral estoppel) that concerns those issues litigated and decided in prior proceedings we now find in England and in the United States.