What is “scutage” in feudal England?

The story behind the answer

In feudal England, tenants who owed knight service could, instead of appearing in arms, pay money based on the number of “knight’s fees” they held. This cash substitution let the crown raise funds to hire professional soldiers, making royal armies more flexible than feudal musters. The practice is reflected in the name itself, from Latin scutum (shield), signaling its link to military obligation.

First used systematically under Henry II and levied heavily by King John, it became controversial; Magna Carta required that such charges be imposed with the “common counsel” of the realm. It was not a general land tax, a fee for peasants’ labor commutation, nor specifically for castle upkeep, but tied to knightly tenure.