A quick look at the list of wealthy individuals from the middle ages, gives us William the Conqueror for someone most of us are familiar with. The wiki list is a bit vague on dollar amounts, so a little more research leads us to another article here which has this to say:
William the Conqueror was a King of England, and had an
inflation-adjusted estimated net worth of $229.5 billion.
(google says that's £172.125 billion)
Since comparing net worth is not a simple issue, the OP is asking for income figures. Digging a little deeper I was finally able to come up for some numbers on William, which show why he was considered one of the richest men in history.
From the Book Taxation, Revenue, Expenditure, Power, Statistics, and Debt of the Whole British Empire; Their Origin, Progress, and Present State: , published in 1833,there is a table which shows the revenue of William the Conqueror:
So £400,000. But this is just one source, so continuing to search, another book showed up discussing this:The History of the Public Revenue of the British Empire : Containing an Account of the Public Income and Expenditure from the Remotest Periods Recorded in History, to Michaelmas 1802; with a Review of the Financial Administration of the Right Honorable William Pitt. By Sir John Sinclair published 1803. On page 70 they get around to discussing the revenue collected by William:
Another match of the £400,000 figure, with a source. Later in the book(pg 72) they discussed the reasons for trusting the figures presented by this source:
...it is impossible totally to discredit the accounts of Vitalis an
historian who was born only nine years after the conquest and
consequently must have enjoyed better access to information than any
modern can pretend to
...Besides Vitalis is so particular in the sum he mentions stating not
only the pounds but even the number of farthings which William
received namely £1,060 30 s 1/2d a day ...that one would suppose his information was derived from authentic records and was not founded on vague or hasty computations.
The historian whose figures are mentioned is Orderic Vitalis, and the wiki page mentions, concerning him:
Modern historians view him as a reliable source.
So we have an estimate of roughly £400,000 for an income for William the Conqueror.
Concerning the laborers wage:
Another quick search for wages at that time gives us a site, The History of England which says:
So a labourer for example, earned £2 a year in 1300
(There is some other good info on the above site as well concerning things such as the value of bread and other wage figures.)
Getting rid of my old attempt at comparing apples and oranges, or trying to translate values to todays' dollars or pounds, we have two numbers £400,000 to £2. Therefor, if we take the 19th century figures at face value, we can conclude that:
- William the Conqueror made 200,000 times the wage of a day laborer.
Not quite the equivalent of Gates 33 million per day, but not inconsequential. It was definitely, as Mel Brooks would say,"Good to be King".