Comma After Introductory Clauses

Introductory clauses are dependent clauses that are often found at the beginning of the sentence (although they can be moved to the end of the sentence, too, without confusing the meaning of the sentence). After a dependent introductory clause, we use a comma to separate the introductory clause from the independent clause. Consider the examples below:

As the man was walking into the store he came face to face with his childhood sweetheart.

As the man was walking into the store, he came face to face with his childhood sweetheart.

Because the rain was torrential the day’s Little League games were postponed.

Because the rain was torrential, the day’s Little League games were postponed.

As with many other rules in English grammar, the comma-after-introductory-clauses rule comes with an exception. When the introductory clause is short, the comma may be omitted as a matter of style. See the example below:

Grabbing her umbrella, Kate raced out of the house.

Grabbing her umbrella Kate raced out of the house.

Since the introductory clause consists of only three words, the comma separating the introductory clause from the main clause may or may not be used.

Introductory Clauses with Dates

Although it is not strictly required, it is considered good style to follow introductory dependent clauses containing dates with a comma. This is true whether the date given denotes a century, a year, a month, or even a day.

In 1776, the Declaration of Independence was signed.

On Tuesday, I received my first paycheck.

In the seventeen hundreds, the minuet was a popular dance style.

In March, we celebrate St. Patrick’s Day.

But if the date does not appear as an introductory clause, no commas are necessary.

The Declaration of Independence was signed in 1776.

I received my first paycheck on Tuesday.

The minuet was a popular dance style in the seventeen hundreds.

We celebrate St. Patrick’s Day in March.