Orig. a punishment imposed by the Romans in which one in 10 was killed. A word used of the extravagant distribution of 10 per cent of his lands by King /Ethelwulf in 854 to the Church and his *thegns before going on pilgrimage to Rome. Kings were expected to be generous; they also expected something in return, usually loyalty. Decimation was also used in referring to *tithes. -
Cf. Dime
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.