 Although a number of postmen succeeded in passing through the Prussian lines in the earliest days of the siege, others were captured and shot, and there is no proof of any post, certainly after October, reaching Paris from the outside, apart from private letters carried by unofficial individuals.For an assured communication into Paris, the only successful method was by the time-honoured carrier-pigeon, and thousands of messages, official and private, were thus taken into the besieged city.During the course of the siege, pigeons were regularly taken out of Paris by balloon.