If anyone ever re-excavates the site of the Teutonic Order's first headquarters in the town of Akko (medieval Acre) in northern Israel, they might come upon an unexpected and rather exciting find - a mobile phone, circa 1999. Once the realisation sets in that this device was not left there by a German crusader rushing to escape the Mamluk hoards in 1291 after making a desperate attempt to phone for help, the future excavator may come to the correct conclusion. The mobile was there due to the absentmindedness of an earlier archaeologist (myself) who had left it in the rush to back-fill the excavation site at the close of season.
Most historians would agree that the crusaders probably did not possess mobile phones. However, they did make use of some other, quite effective means of communication. Perhaps the most interesting of these was pigeon-post, which they employed in their towns and castles, and in the battlefield. They picked this up from their Muslim neighbours who had evolved and extensive pigeon-post system. The idea of using pigeons to carry letters was not new; it had been employed by the ancient Persians and extensively by the Romans; but like many other things, it was lost in the West after the fall of the Roman Empire. In the Middle Ages it returned to Europe and spread into many other regions, and in some cases remained in use until quite recently. The Indian police department for example employed 800 birds, and these were only put out to pasture (or whatever the avian equivalent of that might be) as recently as 2002.
Pigeon post (p-mail) was probably a good deal more efficient than some regular, or to use the often appropriate term - "snail mail" services. In the Crusader period. letters sent by pigeon took considerably less time to arrive at their destination than did those sent by other means of transport. In the Middle Ages letters from the Holy Land to Europe could take several months to arrive. Even in more recent times, letters could be lost or delayed, sometimes for considerable periods. To take one extreme example, there is the case of a letter sent from Paris in 1790 to the town of Seix near Toulouse in south-west France. It was from the authorities in Paris, in answer to a request of Seix officials that their town be made capital of their municipality. It had been sent by mistake to the town of Saix, 150 miles away, and it remained there in the bottom of a drawer in the sorting office until a local archivist found it in 1999. It took another decade to reach its correct destination, a total of nearly 220 years - rather a long time for the town officials to find out that their request had been turned down!