early 13c., "act of raising or collecting," from Anglo-French leve, from Old French levée "act of raising," noun use of fem. past participle oflever "to raise" (see lever). Originally of taxes, later of men for armies (c.1500). Related: Levied; levying.
There are some irregular coin taxes that were paid; the death-tax (heriot), the tax on roads and bridges, the market tax for coming to vend your wares... but those were limited. I've tried to help model the division between coin and kind in terms of gross incomes for the nobility, but the salient point today is that the levee of coin taxes is irregular; the noble class simply did not owe a flat coin tax to their kings or overlords.
When Arunians speak of "raising the tax" what they actually mean is the one-time collection of an arbitrary tax by a royal or imperial power. When the tax is raised, it is by a single decree authorizing a collection of between 5-25% of a noble's gross income over the past year (for which reason they must keep detailed records in their holdings, usually attended to by a bailiff or seneschal).
Taxes are part of the bannum, a Carolingian concept of legal authority related to the Roman idea of manicipium and something we would translate today as "jurisdiction." Raising the bann includes the calling of knight-service on the field as well as the arbitrary levee of taxes. The emperor of Miles may "call the bann" and thus demand the assembly of knights and lords, he may raise taxes to pay for his wars, etc. Most kings or ruling powers in 10th Age Arunia share a similar power and use imperial terms (the bann) to raise taxes, though the emperor's bann is the template for the others and goes farther than most.
Interestingly, the bann is also a term used to refer to some lord's rights—in particular the communal ovens in most towns. Since the ovens are a lord's monopoly (mostly in the empire or imperially influenced lands) using them requires the common folk to pay another labor-service, this one in bread.