Comma after “In Italy” at the beginning of the sentence

Question

Is it necessary to put a comma after "In Italy" in this sentence?

In Italy, there are many historical art pieces.

Could you explane the rule please?

Answer 1

Not to disagree with jboneca's answer, but here's another interpretation.

This is similar to the practice of, say, writing lists of names like this:

• Einstein, Albert
• Shakespeare, William

Or writing inventories like this:

• Coat, brown
• Shoes, leather, black

In each case, we mark the break from the natural order of English ("black leather shoes", "Albert Einstein") with a comma.

The natural order of an English sentence is to put modifiers like in Italy at the end:

There are many historical art pieces in Italy.

But English grammar permits us to move the modifier to the front when it suits our purposes. In speech, we mark this break from the natural order with a change in intonation and a pause. In writing, we mark it with a comma.

Answer 2

This is a prepositional phrase. You can see a list of prepositions here. If a prepositional phrase begins a sentence, it is usually mandatory or wise to place a comma to reduce ambiguity in interpretation. You can see examples of this rule here.

Though it would be unlikely for anyone to be confused about the meaning of that particular sentence, it might still be good practice to include one. I think this is particularly true in strict APA and (possibly) MLA styles.

Chicago style handbooks maintain that a comma is not always mandatory, but instead should only be used a) when a pause is intended or b) the elements of the sentence are complex and varied.

I tend to side with the Chicago school on this one. With such a simple sentence a comma is unnecessary, but certainly not wrong.