Needs Military Tradition and Gunpowder. Research "upper part of tech tree": up to Nationalism and then Military Tradition. Research "lower part of tech tree": up to Gunpowder Ingore most of "middle parts of tech tree. If you are "lucky" you'll get Cavalry before others get Muskets, and if you are just playing well, you'll always get them before others get Granadires or Riflemen. And that means one big advantage. Unit with Strenght of 15 can easly bite Pikemen and Musketeers. Not to mention that there is really no good defense against their pillage ability. And if you in some case play Russians, there are strenght of 18 Cossaks! Best military rush ever for Russians.