What new feature was introduced to the English stage during Restoration?

The most significant new feature introduced to the English stage during the Restoration was the proscenium arch.

Here's why this was so impactful:

* It created a clear division between the actors and the audience. This allowed for more realistic staging and a focus on the actors' performances. Prior to this, the stage was often open, with the audience surrounding the actors on three sides.

* It allowed for the use of painted scenery and elaborate sets. The proscenium arch provided a frame for these, creating a more visually impressive and theatrical experience.

* It led to a change in acting style. Actors were now expected to project their voices and movements towards the audience, leading to a more stylized and theatrical form of performance.

While the proscenium arch was not the *only* innovation of the Restoration period, it was arguably the most important, as it fundamentally changed the relationship between actors and audience, and the way plays were staged.