In the Republic of Venice the protection of public order, economic prosperity and success in military enterprises was protected by a high degree of secrecy.
Already in the first centuries of its history, the Serenissima had to deal with a dangerous internal instability and with the inclination of a part of the patriciate to plot conspiracies for power. In fact, between 717 and 1355, 17 Doges were deposed or executed.
The Conspiracy of Baiamonte Tiepolo and Marco Querini in 1310 marked the decisive moment in which the State was forced to appoint an exceptional tribunal, to investigate and repress seditions and troubles. Permanent authority of the Serenissima since 1335, the Council of Ten specialized in the management of political crimes and secret affairs for state security, with wide autonomy, including economic, towards the other magistrates.
A dense internal intelligence network was set up, consisting of spies and informants, who reported to the chief, the “Missier Grande”, reporting directly to the Council of Ten. International issues were entrusted to investigations by “explorers” coordinated with diplomatic personnel. The killers in charge of bringing the guilty before the judges or (in some cases) to solve the problem in more prominent ways, dealt with repression.
To protect secrecy as much as possible, which became a crucial value for the fate of the Republic, in 1539 the Council of Ten elected a special supervisory authority: the three ‘State Inquisitors’.
For this purpose particular containers, similar to the current mailboxes, were distributed in the city, especially near the institutional offices (Palazzo Ducale was the first place) in which to introduce secret but strictly non-anonymous complaints, under penalty of their destruction and destinated to the Inquisitors.
These containers had the appearance of open jaws on the outside. They were often carved with lion-like features or decorated with masks and took the name of “boche de leon” (lion’s mouth). Currently in the city 16 lion’s mouth are still visible.