Okay, so imagine you really like ice cream. Yum! Well, the Neapolitan School is kind of like a big bowl of ice cream that has three different flavors in it: chocolate, vanilla, and strawberry. Each flavor is its own thing, but they're all mixed together in the same bowl.
Now, instead of ice cream, we're talking about music. The Neapolitan School was a group of composers who lived in a city called Naples in Italy a long time ago. They liked to write music that had three different parts, kind of like the three flavors of ice cream in our bowl.
The first part was called "the cantata." This was like the chocolate ice cream in our bowl. It was usually a solo song that someone would sing, and it was kind of slow and pretty.
The second part was called "the aria." This was like the vanilla ice cream in our bowl. It was usually also a solo song, but it was faster and a little more playful than the cantata.
The third part was called "the tarantella." This was like the strawberry ice cream in our bowl. It was really fast and lively music that people could dance to.
So, when the Neapolitan School composers put all three of these parts together, they created a special kind of music that was really popular at the time. It's like if you mixed chocolate, vanilla, and strawberry ice cream all together in one bowl - it would be really tasty!