A well-known exception to Grimm’s Law, /kʷ/ > /f/ instead of /kʷ/ > /hʷ/, is taken as a starting point and its reflexes in Middle Dutch and Sal-Frankic are discussed. As to the PIE root *leikʷ-, MD and MLG līf- in the compounds līfeigen ‘owned by the fief’, līftuht ‘feudal law’, and līfcōp ‘feudal transaction fee’ is identified as derived from this root under a regular sound change, which is coined Uhlenbeck’s Law. Uhlenbeck’s Law acts as a resolution of a pansyllabic constraint, not a constraint on roots. As to Sal-Frankic, the new etymology of SF leo- ‘related to the tenements’’, and by extention ‘agricultural’, sheds new light on the structure of the Lex Salica. It is argued that the tripartite manorial system of land tenure has reflexes in juridical terminology of this archaic legal document.