One of the great English country mansions is Audely End House, though it is only a fraction of its original size. Thomas Howard, first Earl of Suffolk, and Lord Treasurer of England from 1614-1618, built it in 1603 to 1616. It was rumored that Howard embezzled a lot of money from the royal treasury. It is said that when King James VI & I visited, he said that Augdley End was too big for a king, but just right for a lord treasurer. He was tried and convicted of embezzlement in 1619. He spent time in the Towar of London before being released.
https://en.wikipedia.org/wiki/Audley_End_House
Nicholas Fouquet (1615-1680) Marquis of Belle-Ile, should have paid more attention to that story. He was Superintendent of Finance from 1653 to 1661. From 1641 to 1661 he bilt splendid gardens and a great mansion at his estate Vaux-le-Vicomte. In 1661 King Louis XIV attended a great party at Vaux-le-Vicomte and was impressed by the great wealth and splendor on display, so much that he later hired the architect, painter, and gardener to work at Versailles.. Fouquet was arrested soon after and he was sentenced to life imprisonment for corruption in 1664.
https://en.wikipedia.org/wiki/Vaux-le-Vicomte
James Brydges (1673-1744), 9th Baron Chandos, had many government offices, and was made Earl of Carnavaron in 1714 and Duke of Chandos in 1719. And he was Paymaster of the Forces (overseas troops of the British Army) from 1705-1713, during the War of the Spanish Succession. He also became extremely wealthy during his time in government, and was suspected of embezzlement. His country estate and Manson of Cannons was one of the greatest of the era, and its reputation was highly exaggerted over the truth.
https://en.wikipedia.org/wiki/Cannons_(house)
The first Duke of Chandos made unwise investments and people said that what he gained by corruption he lost by speculation. His heir had to sell Cannons for parts to pay off crushing debts. The 3rd Duke of Chandos died without a son in 1789, making the title extinct.
The third Duke's daughter, Lady Ann Elizabeth (1779-1836) married in 1796 Richard Temple-Nugent-Grenville, 2nd Marquess of Buckingham (1776-1839) who changed his surname to Temple-Nugent-Chandos-Brydges-Grenville in 1799. In 1822 he was made Earl Temple of Stowe, Marquess of Chandos, and Duke of Buckingham and Chandos.
The temple faily motto was "How sweet are the Temples". Dear is a synonym for "sweet", and also for "expensive", and it was suggested their motto should be "how Dear are the Temples", implying a belief that a lot of their wealth came from corruption. And the size of their wealth, howeve acquired, can be seen by visiting the Temple-Nugent-Chandos-Brydges-Grenville former estate and mansion at Stowe.
https://en.wikipedia.org/wiki/Stowe_House
Going back to the time of the First Duke of Chandos, the Captain-General of the British army in the war of the Spanish Succession from 1702 to 1711 was John Churchill (1650-1722), the first Duke of Marlebrough, and Prince of the Holy Roman Empire. And I read somewhere that when the Duke died and his will was probated someone reported that his wealth was over a million pounds (then worth many times more than today) and claimed that was proof of Marlborough's corruption.
The Duke of Marlborough was presented with a country estate by a grateful nation and the government voted some money to build him a magnificent mansion, Blenheim Palace, as a monument to his glory. The Duke and the governmet both paid for the conastruction of Blenheim Palace from 1705 to 1712, and work stopped. The Duke resumed construction of Blenheim Palace in 1716. After the Duke suffered a stroke in 1717 his wife took charge, and cut expenses as much as she could, After the Duke died in 1722 she continued building until sometime in the 1730s.
And anyone who sees Blenheim Palace will have to agree that if the Marlboroughs paid a significant percentage of the total cost they must have had geat wealth - ill-gained or not.
https://en.wikipedia.org/wiki/Blenheim_Palace#
So I find it amusing to read that:
The 1st Duke, as a soldier, was not a rich man and what fortune he possessed was mostly used for finishing the palace.
https://en.wikipedia.org/wiki/Blenheim_Palace#Failing_fortunes
Marlborough's great ally was the Austrian general Prince Eugene of Savoy.
Here is a link to an article about his winter palace in Vienna.
https://en.wikipedia.org/wiki/Winter_Palace_of_Prince_Eugene
Prince Eugene's summer residence in Vienna, the Belvedure gardens and estate, contains two palaces.
https://en.wikipedia.org/wiki/Belvedere,_Vienna
I don't know what the job of a "war commissioner" was in the 18th century. But I hope that the examples I gave should demonstrate that many people would cynically believe that high officials would gain great wealth from their jobs.
Maybe you shoud ask this hquestion in the history stack exchange.
Anyway, these examples show that in those days important civilian and military government officials were often very rich, and were often accused - accurately or not - of acquiring vast fortunes by vast corruption.