How did the great houses of 15th century England 'manage their assets'?

How did the noble houses of England extract wealth from their holdings? What sort of 'bureaucracy' existed within these noble houses to manage their wealth? Which houses seemed to most effectively leverage what they owned? From an althistory perspective, what sort of 'bookkeeping' or 'investment' practices could these noble houses have adopted from elsewhere that would have improved their ability to extract wealth?
 
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