what does it mean

[katiev]

where does the saying work as hard as a trogon

[jno]

it's work like a Trojan - the people from ancient Troy (as in the Brad Pitt movie). They're supposed to have been hard-working types, but the phrase didn't come into use until the 19th century, apparently - about 3,200 years later.

[Quizmonster]

The word 'Trojan' has been used in English since the 1300s to mean a person of great strength, bravery and endurance...based on the characteristics of the warriors of ancient Troy, as Jno says. Hence, 'like a Trojan' has been applied in various situations to suggest these qualities.

[jno]

I must have been misinformed - okay, make that a mere 2700 years later.

[Quizmonster]

You were perfectly correct, Jno, to say that "work like a Trojan" - the specific version of the phrase under discussion here - dates back to the 19th century. I was trying to point out to the questioner - just as a matter of interest - that Trojans had been held up as examples of fine qualities in spheres other than work for rather longer...ie a bit of extra information.
(Excavations at Hissarlik in Turkey reveal that Troy existed as long ago as 3000 BC. Thus, when Cardinal Newman used the phrase "working like a Trojan" in 1846, he did so perhaps as much as 5,000 years after the hardy Trojans first settled there!