This may be heresey but i have been using massed mortars.

Because they fire (way) over the heads of your men they can keep going even when the enemy is engaged with your troops and i always find cannons difficult to defend from attack.

still with four or five motar units providing death from above most units don't last that long.

They are also great for pummeling massed formations in a city or castle square

has anyone else tried this or is it just me?