What happened after Caesar denied the crown?

He then had a seizure.

Since, Brutus was the one to explain about Caesar's behavior he thinks that what caused Caesar to have a seizure was falling-sickness (aka epilepsy).

He refused it the third time, and as he refused it the commoners hooted and clapped their hands, and threw up their sweaty hats, and let loose such a great deal of stinking breath because Caesar refused the crown that it nearly choked Caesar, because he fainted and fell down.