In the process of formation of national monarchies, in the late Middle Ages, we observed that several secrets and treasures of the State were very carefully guarded. After all, treaties and treasures were items of paramount importance in securing the interests of a monarch or in the economic strengthening of a nation. In this context, we observed that it was quite common to use chests, which were kept in strict secrecy.
This habit was largely responsible for the conception of the term “kept under lock and key”, commonly used when we must keep or are keeping a secret of paramount importance. In fact, the relationship of the term with the old habit of the courts is due to the use of different keys in the process of locking these chests. Only, instead of seven keys, the chests of that time had only four keys that were distributed among people who were fully trusted by the monarch.
Thus, the curious question remains: “If the chests of the period had four keys, why do we say that the secret is kept under seven keys?”. It is at this time that the religiosity and mysticism of those times come into play to explain these “other keys” of our investigated expression. Already in antiquity, long before the emergence of national monarchies, the number seven was used as a powerful symbol of perfection and sacredness.
Some ancient religions of the Fertile Crescent performed rituals of worship to the seven planets known up to that time. In the medieval period, wills were sealed with seven seals and the formulation of these same documents also had the participation of seven witnesses. In the biblical narrative itself, the number seven appears several times as a means of referring to the divine figure or to actions performed perfectly.
In such a way, when we say that a secret or treasure is “kept under lock and key”, we remember all this symbolic tradition given to the number seven. Apparently, the origin and secrets surrounding the explanation of this term already have all seven keys unlocked.
By Rainer Sousa
Master in History
Brazil School Team
Curiosities - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/curiosidades/origem-da-famosa-frase-guardado-a-sete-chaves.htm
