Great officers of the realm were important people in the time of kings and queens from long ago. They were like a big team of grown-ups who helped the king or queen run their kingdom.
There were four main great officers:
1. The Lord Chancellor - who was in charge of important papers, like laws and letters
2. The Lord Treasurer - who was in charge of all the money and making sure there was enough to pay for things
3. The Lord Steward - who was in charge of important events like feasts and weddings
4. The Lord Chamberlain - who was in charge of the royal household and making sure everybody who worked there did their jobs properly
The people who were great officers were picked by the king or queen because they were trusted and known to be good at their jobs. They were allowed to do important things and make decisions about the kingdom, but they always had to make sure the king or queen was happy with what they were doing.
In the olden days, being a great officer was a very important and respected job, like being a superhero for the kingdom!