Form Fitting Armour

[Roach XI the Magnificent]

Some of the roman generals fought in the front lines, notable examples are Pompei leading cavalry charges and Julius Cesar standing in the front of the battleline. Even a well drilled professional army still have a breaking point.

Indeed, but every rule has exceptions. Look at, say, Japanese or Persian generals sometimes getting into the fray as well.

[Talq]

Alexander the Great was close to the last leader to, as a rule, lead from the front, rather than co-ordinate from the rear. It became generally accepted the the role of the general was to react to the course of the battle by deploying forces to take advantage of opportunities rather than swing their sword like another grunt. In addition the death of the general would likely lose the battle and especially if they were a king probably have more far reaching effects on the losing side.

While there were exceptions they don't invalidate the rule. To take the example of Julius Caesar, he joined the battle line only once (and there is some doubt he even did that) in all his campaigns, in a situation where he had no other options.

 

[Amman de Stazia]

At the Battle of Dettingen, King George of England led a cavalry charge in person.  This is the last documented instance of a ruler of England or the United Kingdom entering combat.



Alexander the Great was the last ruler to lead from the front?

I'll stop now, before I insult you.

[xenoargh]

Leading from the front is still a widely-used practice; duels between leaders to settle the affairs of nations, not so much.  I blame artillery. 

Imagine Napoleon trying to arrange a battlefield duel at Waterloo:

"I say there!  It appears as if some wee dot over there is advancing towards us!  It could be Napoleon, riding forward to deliver a challenge to our generals to settle this whole dreary thing with a bit of the old sharp and nasty, what?"

"Oh dear; Battery 5 opened fire along that lane a few moments ago, sir.  The fuses were so nicely timed, but what of the honor of the army, should one..."

<puffs of black smoke appear 100 meters in front of Napoleon and his seconds>

"...detonate early?  Oh, dear."

That is why generals don't fight duels any more. 

It's really too bad; I think I speak for a lot of people when I say I would have paid good money to watch the Allied commanders fight Osama and the Taliban's leadership with steak knives on TV to settle who got ownership over the miserable countryside that they currently dispute via ambushes and robotically-controlled death machines instead. 

Modern warfare's sheer distance makes it impractical and nobody is dumb enough to agree to fight a duel whilst surrounded by the other guy's machine guns.

[Amman de Stazia]

Well, it would have had to be done tastefully, you know - with proper Halal slaughter training beforehand so that nobody could be offended by an improper killing blow.

[Swadius 2.0]

"Oh dear; Battery 5 opened fire along that lane a few moments ago, sir.  The fuses were so nicely timed, but what of the honor of the army, should one..."

I thought the British used flint ignitions at this point. I know the British cannons at Trafalgar did. Also, I disagree with ranged warfare contributing all that much to the decline of duels between commanders. In order for duels to take place, you need a lot of trust in the opposing commander and the opposing side's politicians as well that they will uphold the agreement on which the duel will be fought upon.  In Greek city states, I think it is far more common for the elite of the cities to actually know each other in person and to build a reliable character of them.

It's also the case of public pressure on people who decline in person duels. In a Greek society, honor might have been incredibly important to one's public standing. In particular one's martial honor. Most societies beyond this one never had as much invested into this ideal as the Greeks have. We may see some commanders or military elites espousing a certain similarity, but the civilian population nor the civilian political entities felt it to be all that important. Thus there weren't much consequence of declining an offer to duel to settle the battle.