Playing as Napoleon/French in Civ5, I am struggling to get the "Three Musketeers" achievement. I suspect the answer is somewhere in what is considered to be "flanking" (How do you flank an enemy?), but not quite sure. Has anyone achieved this, and know how to get it?
This is a tricky one, mostly because it's got some very specific conditions you're unlikely to encounter in normal play.
First, you're going to need at least 3 Musketeer units. Advancing the start age so that you don't have to grind through a bunch of low-level techs to get to the gunpowder age speeds this up. Play on an easy difficulty level so that producing the units is fast. Having more than three is better - if you can completely surround the unit with Musketeers, you'll have a much easier time of it.
Second, you need a unit that you can trap and then kill. City States will have units wandering around that you can surround, or you can play on a mountainous map with another civ. I don't believe this one is doable in a hotseat game between two players, sadly.
Third, you've got to flank the enemy unit with your Musketeers. Contrary to my previous belief, this just means having several units in hexes adjacent to the same enemy unit.
Finally, you've got to kill it with your attack. I'd suggest saving first, and then weakening the unit if the odds aren't overwhelming that you'll kill with one hit. Policies in the "Honor" track can be helpful here, as they'll impart combat bonuses you might find beneficial.
A flanking bonus in Civ V is given when you attack an enemy unit while one of your other units is adjacent to it. This represents the tactical value of surrounding the enemy.
To do this achievement, you need to be playing as France and to have three musketeer units. Naming them is optional but for this example we'll call them Porthos, Athos and Aramis. You'll also need an enemy unit- city states tend to have some around. Using a city state for this also means you don't need to declare war until you're in position.
Your victim needs to be a military unit and should be weak enough that your musketeers can kill it. Most pre-gunpowder units will do. Better still, bring ranged units along to weaken the enemy.
Use the ranged units to weaken the enemy, then move Athos and Aramis next to it. Finally, have Porthos attack and kill it. He should get a bonus from the musketeers and you should get the achievement.