Got a Real-World Weapon, Armor or Tactics Question? Mk. XXV

[Mabn]

Spears never "became two-handed", pikes came into use but they're not simply a longer spear. Spears remained one-handed, because they were almost always partnered with a shield. They were counter-weighted to keep them handy with one hand.

Some lances were used two-handed, like the xyston and kontos.

any reason both those lances were from way before the invention of the stirup? Like, did 2 handed lances stop being efficient?