What did a soothsayer warn Julius Caesar to be cautious about?

Throughout the play, two soothsayers warn Julius Caesar to be aware of the senators who are conspiring to assassinate him on March 15th. In Act One, Scene 2, a soothsayer warns Julius Caesar to "Beware the ides of March" (Shakespeare, 1.2.20). The Ides of March is a day on the Roman calendar that corresponds to March 15th, which is when the Roman senators plan on assassinating Julius Caesar. Caesar does not heed the soothsayer's warning and goes against his wife's wishes to travel to the Senate. Before Caesar enters the Senate floor, Artemidorus, who is also a soothsayer, gives Caesar a letter that warns him to stay away from the jealous senators. Artemidorus's letter tells Caesar to avoid Brutus, Cassius, Casca, Cinna, Trebonius, Metellus Cimber, Decius Brutus, and Caius Ligarius, because they plan on harming him. In Act 3, Scene One, Caesar travels to the Senate floor and confidently informs the soothsayer, "The ides of March are come" (Shakespeare, 3.1.1). The soothsayer responds by telling Caesar that the day is not over. Artemidorus then gives Caesar his letter, warning him about the dangerous senators, and urges Caesar to read the letter immediately. Unfortunately, Caesar does to read the letter before addressing the senators and is assassinated on March 15th.