What is the origin of the idiom "the more the merrier" and when to use it?

The idiom "the more, the merrier" is a traditional English proverb with origins dating back to at least the 16th century. Its exact source is not pinpointed, but it reflects a sentiment that is shared in various cultures worldwide. This phrase is used to express the notion that adding more people to a gathering, activity, or celebration can make it livelier, more enjoyable, or more festive.