Judged by an absolute rather than a contemporary standard, there is much to criticise in the collection of the danegeld by the early 12th century: it was based on ancient assessments of land productivity, and there were numerous privileged reductions or exemptions, granted as marks of favour that served to cast those left paying it in an "unfavoured" light: "Exemptions were very much a matter of royal favour, and were adjusted to meet changing circumstances ... in this way danegeld was a more flexible instrument of taxation than most historians have been prepared to allow." Henry I granted tax liberties to London in 1133, and exempted the city from taxes such as , danegeld, and murdrum.