Marcellus, a sentry

[This is an annotated list of all appearances and all mentions of Marcellus.]
Jack Lemmon as Marcellus
"And liegemen to the Dane" (1.1.15). He assures Francisco that he and Horatio are loyal to the King, then he and Barnardo try to persuade Horatio that they really have seen a Ghost. [Scene Summary]
"My good lord" (1.2.165). He accompanies Horatio and Barnardo to tell Hamlet of the Ghost. [Scene Summary]
"No, it is struck" (1.4.4) Marcellus goes with Horatio and Hamlet to await the Ghost. It is Marcellus who, towards the end of Act 1, Scene 4, utters the famous line, "Something is rotten in the state of Denmark" (1.4.90). [Scene Summary]
"Lord Hamlet!" (1.5.112). Horatio and Marcellus catch up with Hamlet after the Ghost has spoken to him. [Scene Summary]