Okay buddy, so first let's break down the title, "atabegs of yazd." Atabegs were sort of like governors or protectors of important people in the olden days, like knights or bodyguards. Yazd is a city in Iran, which is a big country on the other side of the world.
So the atabegs of Yazd were basically important people who were in charge of keeping other important people safe in Yazd a really long time ago. They were like the best of the best at protecting people and they were respected for their skills.
Sometimes these atabegs would even become rulers themselves, and they would be responsible for making decisions for the city and the people living in it. They made sure that everyone in Yazd was safe and happy.
But this was all a really long time ago, buddy. Today, Yazd is a really beautiful city with lots of history and culture. You can visit and see some of the amazing buildings and monuments that the atabegs helped build thousands of years ago!