The reason mentioned by Vibullius is trivial, namely that you were delayed on hearing that Caesar had left Firmum and arrived at Castrum Truentinum.
The ancient Firmum Picenum was founded as a Latin colony in 264 B.
The army occupied standing quarters near Firmum in Picenum, where by command of the senate the legions defeated on the Siris spent the winter by way of punishment under tents.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "firmum" in a variety of sentences. We hope that you will now be able to make sentences using this word.