If my maths is right (and it probably isn't), Trojan horses will be 3193 years old tomorrow.
Yes, according to military historians the city of Troy fell to the Greeks on April 24, 1184 BC, following a ten year siege.
Of course, no-one would fall for that kind of trick in these enlightened times would they..
When I first started working in the computer security field in the early 1990s, it wasn't uncommon to find "dirty dozen" lists posted on Bulletin Board systems like Fidonet of known bad programs. The idea was that you would memorise the list, and would be careful not to download that particular program.
Can you imagine that working now?
Although Trojan horses faded into the background as the 1990s progressed and malware authors concentrated on spreading their self-replicating viruses and worms as far and as wide as possible, the emergence of financially-motivated criminals in recent years has turned things around once more. We see more Trojan horses today than viruses or worms. Most of the malware SophosLabs encounters is written to steal from your PC via a Trojan horse.
Whether the end goal is to steal your identity or consume your bandwidth by turning your PC into part of a spam-spewing botnet this isn't a Trojan war being fought over the beauty that was Helen of Troy, but a fight for your hard-earned money.