Security was a Guardian Angel

In India, in the days of the Emperor of Annam, valuables were sealed into large blocks of wood, which were placed on small islands or submerged into surrounding pools of the inner courts of the palace. Here, they were protected by the royal "guardian angels," a number of crocodiles kept on starvation rations so they were always hungry. To venture into the water meant certain death for the intruder. The legitimate approach to the treasure was to drug or kill the crocodiles.