Hey there kiddo! So in the year 1627, there was this thing called the Popery Act. It was a law made by the government of England (which is where we live, remember?) that basically said that Catholics (a type of Christian) could not practice their religion freely.
See, at that time, most people in England were Protestants (another type of Christian), and the government didn't really like Catholics. They thought they were a bit weird and maybe even dangerous.
So, the Popery Act said that Catholics couldn't have Catholic priests coming into England from other countries to do religious ceremonies (like Mass), they couldn't own land, and they couldn't work certain jobs. Basically, it made life really tough for them if they wanted to practice their faith.
Now, we know that it's not fair to discriminate against someone because of their religion (that means treating someone differently just because of what they believe in). But back then, things were different and people didn't always get along.
Eventually, the Popery Act was repealed (which means it was canceled) in 1829, and Catholics were allowed to practice their religion more freely. It took a while for things to change, but it's good to remember that we should always treat everyone with kindness and respect, no matter what they believe in.