A more thorough explanation:

The Undertreasurer of England was a historical officer who worked under the Lord High Treasurer. Their role was to assist the Lord High Treasurer in managing the finances of England.

For example, during the reign of King Henry VIII, Sir William Paulet served as the Lord High Treasurer, and Sir John Williams served as the Undertreasurer of England. Williams was responsible for overseeing the collection of taxes and managing the royal accounts.

The Undertreasurer of England was an important position in the English government, as they played a key role in ensuring that the country's finances were managed effectively. They were responsible for overseeing the collection of taxes, managing the royal accounts, and ensuring that the government had enough money to carry out its duties.