Question: What Shakespearean play has a pair of brothers where one inherits the throne, and the other flees to Ireland after their father's murder?

<P0-S0> Donalbain is a character in William Shakespeare's "Macbeth" (c. 1603–1607). <P0-S1>  He is the younger son of King Duncan and brother to Malcolm, the heir to the throne. <P0-S2>  Donalbain flees to Ireland after the murder of his father for refuge. <SEP> <P1-S0> Across the Plains is a 1911 American western directed by Broncho Billy Anderson and Thomas H. Ince and starring Anderson. <P1-S1>  The film's plot has Jennie Lee and her father heading to California in a prairie schooner. <P1-S2>  Jennie Lee's father becomes intoxicated before Indians attack them for trespassing on the land. <P1-S3>  Unable to convince her father to get in the carriage, Jennie Lee flees and races the Indians and is led to a deserted shack by a cowboy as his partner heads off for aid. <P1-S4>  The two are saved as the ranchmen return and disperse the Indians. <P1-S5>  The film was not released with a cast of credits as typical of its production era. <P1-S6>  The production took place on the Miller Brothers 101 Ranch and released under Essanay's license. <P1-S7>  The completed film was approximately 990 feet in length and was met with mixed reviews. <P1-S8>  The film's status is unknown, but likely lost. <SEP> <P2-S0> Malcolm is a character in William Shakespeare's "Macbeth" (c. 1603–1607). <P2-S1>  The character is based on the historical king Malcolm III of Scotland, and is derived largely from the account in "Holinshed's Chronicles" (1587), a history of Britain. <P2-S2>  He is the elder son of King Duncan, the heir to the throne, and brother to Donalbain. <P2-S3>  In the end, he regains the throne after mustering support to overthrow Macbeth. <SEP> <P3-S0> Polybus (Greek: Πόλυβος ) is a figure in Greek mythology. <P3-S1>  He was the king of Corinth and husband of either Merope or Periboea. <P3-S2>  He raised Oedipus as his adopted son, who had been abandoned by his parents Laius and Jocasta of Thebes in Greece. <P3-S3>  Polybus was the true father of Alcinoe. <P3-S4>  In virtually all accounts of the mythology, when Oedipus reached adolescence, he consulted with the Delphic Oracle, who told him "You shall kill your father and marry your mother". <P3-S5>  Obviously horrified and disgusted with such a prophecy, Oedipus imposed self-exile upon himself and kept away from Corinth, as he resolved never to murder King Polybus, who had been a kind father to him. <P3-S6>  Oedipus was also understandably disgusted the act of murdering Polybus and claiming his wife for himself, as he had no unnatural attraction to Queen Merope. <P3-S7>  Many years later, after Oedipus won the kingship of Thebes by defeating the Sphinx, did another plague befall Thebes. <P3-S8>  King Oedipus, in his effort to find the cause of plague due to a patricide, revealed that he was told in his teen years that he was destined to murder his father, and sent a spy to Corinth to see who is currently on the throne. <P3-S9>  The news of Polybus' death by natural causes was announced by the messenger to Jocasta in Sophocles' "Oedipus Rex", in which it is mistakenly taken to mean that Oedipus did not kill his father. <P3-S10>  This would mean that the prophecy that Oedipus would murder his father and marry his mother would be false, and Oedipus expresses relief that he did not commit such a heinous act. <P3-S11>  Since Polybus was in fact his adoptive father, Oedipus could and did kill his true father, King Laius, and fulfill the prophecy. <P3-S12>  Oedipus never knew his true destiny until the final parts of the play.