Sejanus His Fall, a 1603 play by Ben Jonson, is a tragedy about Lucius Aelius Sejanus, the favourite of the Roman emperor Tiberius.
Sejanus His Fall was performed at court in 1603, and at the Globe Theatre in 1604. The latter performance was a failure. According to Jonson, an unnamed co-author "had good share" in the version of the play as it was "acted on the public stage". For reasons unknown the play was accused of promoting "popery and treason". Jonson was questioned, but no action was taken.
Jonson published the play in a revised version, replacing the contributions of his co-author with his own words. The published version was accompanied by copious marginal notes citing its historical sources, in quarto in 1605 and in folio in 1616.