Return
to
Twelfth Night,
Act 4, Scene 1, line 59.

Note to Twelfth Night, 4.1.59, "He started one poor heart of mine in thee."

Olivia's "heart of mine" is "in thee" because she's in love with Cesario. (At the moment she's talking to Sebastain, but she thinks she's talking to Cesario.) Olivia's "heart of mine" is "one" because the power of love has doubled her heart, so that she has one heart in herself and one in Cesario.

Also, the word "heart" may play on "hart" (deer). Deer were hunted by being "started" (driven, by beating the bushes) out of cover into the open, where they could be shot.

A Started Hart
Hart