[Cas.]  Did Caesar swound?
  Casca.  He fell down in the market-place, and foam’d at mouth, and was speechless.
  Bru.  ‘Tis very like, he hath the falling sickness.
  Cas.  No, Caesar hath it not; but you, and I,
And honest Casca, we have he falling sickness. 

Julius Caesar, 1.2.251-56

Mark Anthony thrice offers Caesar the crown of Rome, and Caesar thrice refuses it, playing the coy mistress. To Caesar’s surprise, however, his audience applauds his rejection of Roman rule. In response, like an indignant schoolgirl set to rob the world of the pleasure of her existence, Caesar offers to cut his own throat, but he quickly sees better means to his end. He feigns an epileptic fit: the historical Caesar may well have had epilepsy, and Shakespeare’s too, but Shakespeare’s Caesar is also an accomplished actor, one who can act epilepsy on cue. After his show, the audience, overcome with pity, puts its ankles up and spreads its legs for Caesar. What Shakespeare shows in this episode is the remarkable maleability of the meaning of physical affliction, and his play dramatizes the making of multiple meanings. For, in this episode, epilepsy has three meanings, maybe more, depending on who is making the meaning: to Caesar, his false epileptic fit is a sign of his strength, his political acumen, his ability to manufacture public sentiment about himself and control his own destiny; to the crowd, it is a sign of his weakness, of his humanity and mortality, and therefore his likeness to them; to Cassius, who later relates the episode to Brutus and Casca, the falling Caesar is a sign of a falling Rome, on the order of the king’s – or in this case the emperor’s – two bodies. To us in the audience, Caesar’s seizure is not a sign, as in a symbol with a static sense, but a marker, as in a placeholder for symbolization; it is a moment that collects the multiple meanings we make of disabilities, meanings not absolute because written into nature but contingent because grafted on by culture. In other words, Caesar's "falling sickness" does not testify to the legibility of disability in Shakespeare's drama, as has been suggested. Instead, it demonstrates the dramatization of the polysemeity of stigma in Shakespeare and in life. 

Context 

Julius Caesar’s Epilepsy in Early English Literature
Epilepsy in Shakespeare

Bibliography

Hobgood, Allison P. “Caesar Hath The Falling Sickness: The Legibility Of Early Modern Disability In Shakespearean Drama.” Disability Studies Quarterly 29.4 (2009): n. pag.