Title: Menelaus
Content:  Menelaus was a descendant of Pelops son of Tantalus. He was the younger brother of Agamemnon, and the husband of Helen of Troy. According to the usual version of the story, followed by the Iliad and Odyssey of Homer, Agamemnon and Menelaus were the sons of Atreus, king of Mycenae and Aerope daughter of the Cretan king Catreus. Grimal, s.v. Menelaus; Hard, pp. 355, 507, 508; Collard and Cropp 2008a, p. 517; Gantz, p. 552; Parada, s.v. Menelaus; Euripides, Helen 390&ndash;392, Orestes 16; Hyginus, Fabulae 97; Apollodorus, E.3.12; Scholia on Iliad 1.7  (citing "Homer" = Hesiod Catalogue of Women fr. 137a Most) and Scholia on Tzetzes' Exegesis in Iliadem 1.122 (citing "Homer" = Hesiod Catalogue of Women fr. 137c Most). They are also the sons of Atreus, in the 
Title: Menelaus
Content:  and Odyssey, see for example Iliad 11.131, Odyssey 4.462, although Aerope is not mentioned (see Gantz, p. 522). See also Euripides, Iphigenia in Tauris 4&ndash;5, (Atreus as father, no mention of mother); Hesiod Catalogue of Women fr. 138 Most [= fr. 195 MW], and Sophocles, Ajax 1295&ndash;1297 (Aerope as mother, no mention of father). However, according to another tradition, Agamemnon and Menelaus were the sons of Atreus' son Pleisthenes, with their mother being Aerope, Cleolla, or Eriphyle. According to this tradition Pleisthenes died young, with Agamemnon and Menelaus being raised by Atreus. Agamemnon and Menelaus had a sister Anaxibia (or Astyoche) who married Strophius, the son of Crisus. According to the Odyssey, Menelaus had only one child by Helen, a daughter Hermione, and an illegitimate son Megapenthes by 
Title: Menelaus
Content:  slave. Other sources mention other sons of Menelaus by either Helen, or slaves. A scholiast on Sophocles' Electra quotes Hesiod as saying that after Hermione, Helen also bore Menelaus a son Nicostratus, while according to a Cypria fragment, Menelaus and Helen had a son Pleisthenes. The mythographer Apollodorus, tells us that Megapenthes' mother was a slave "Pieris, an Aetolian, or, according to Acusilaus, ... Tereis", and that Menelaus had another illegitimate son Xenodamas by another slave girl Cnossia, while according to the geographer Pausanias, Megapenthes and Nicostratus were sons of Menelaus by a slave. The scholiast on Iliad 3.175 mentions Nicostratus and Aethiolas as two sons of Helen (by Menelaus?) worshipped by the Lacedaemonians and another son of Helen by Menelaus, Maraphius, from whom descended the Persian Maraphions.
Title: Menelaus
Content:  In Greek mythology, Menelaus was a king of Mycenaean (pre-Dorian) Sparta. According to the Iliad, Menelaus was a central figure in the Trojan War, leading the Spartan contingent of the Greek army, under his elder brother Agamemnon, king of Mycenae. Prominent in both the Iliad and Odyssey, Menelaus was also popular in Greek vase painting and Greek tragedy, the latter more as a hero of the Trojan War than as a member of the doomed House of Atreus.
Title: Megapenthes (son of Menelaus)
Content: stalwart Megapenthes, who was his [Menelaus's] son well-beloved, born of a slave woman; Menelaus had ... by a female slave Pieris, an Aetolian, or, according to Acusilaus, by Tereis, he had a son Megapenthes;" Megapenthes was mentioned as early as Homer's Odyssey, where Menelaus marries him to the Spartan Alector's daughter, and is described as: The mythographer Apollodorus, says that the name of his slave mother was Pieris or Tereis: According to the geographer Pausanias, because Megapenthes and his brother Nicostratus were the sons of Menelaus by a slave, and thus illegitimate, Agamemnon's son Orestes succeeded Menelaus as king of Sparta. Pausanias also says that, according to the Rhodians, when Orestes was "still wandering" (being chased by the Erinyes because of his killing of his mother Clytemenestra), Nicostratus and Megapenthes drove out Helen, who found refuge on Rhodes with Polyxo. Pausanias reports seeing Megapenthes and Nicostratus depicted riding a single horse, on the sixth century BC Doric-Ionic temple complex at Amyclae known as the throne of Apollo, designed by Bathycles of Magnesia.
Title: Menelaus
Content:  Although early authors, such as Aeschylus refer in passing to Menelaus' early life, detailed sources are quite late, post-dating 5th-century BC Greek tragedy. According to these sources, Menelaus' father, Atreus, had been feuding with his brother Thyestes over the throne of Mycenae. After a back-and-forth struggle that featured adultery, incest, and cannibalism, Thyestes gained the throne after his son Aegisthus murdered Atreus. As a result, Atreus' sons, Menelaus and Agamemnon, went into exile. They first stayed with King Polypheides of Sicyon, and later with King Oeneus of Calydon. But when they thought the time was ripe to dethrone Mycenae's hostile ruler, they returned. Assisted by King Tyndareus of Sparta, they drove Thyestes away, and Agamemnon 
Title: Menelaus of Macedon
Content: Menelaus, father of Amyntas II or Amyntas III king and grandfather of Philip, according to Justin (vii. 4) and Aelian ( V. H. xii. 43). But there is much discrepancy on this point: Dexippus (ap. Syncell. p. 263, a.) calls the father of Amyntas III as Arrhidaeus; and Diodorus (xv. 60), Tharraleos. Justin represents him as brother of Alexander I which seems a gross error. (See Clinton, F. ff, vol. ii. p. 225.) ; Menelaus (son of Amyntas III) by his second wife. He was put to death by his stepbrother Philip II in 347 BC ; Menelaus (son of Lagus) priest, general and brother of Ptolemy I Soter ; Menelaus, father of the cavalry officer Philip (son of Menelaus) ; Menelaus of Pelagonia honoured in Athens Menelaus of Macedon (, Menelaos) may refer to: 
Title: Menelaus
Content:  Book 4 of the Odyssey provides an account of Menelaus' return from Troy and his homelife in Sparta. When visited by Odysseus' son Telemachus, Menelaus recounts his voyage home. As happened to many Greeks, Menelaus' homebound fleet was blown by storms to Crete and Egypt where they were becalmed, unable to sail away. They trapped Proteus and forced him to reveal how to make the voyage home. After their homecoming, Menelaus and Helen's marriage is strained; Menelaus continually revisits the losses of the Trojan War, particularly as he and Helen have no male heir. Menelaus is fond of Megapenthes and Nicostratus, his sons by slave women. According to Euripides' Helen, Menelaus is reunited with Helen after death, on the Isle of the Blessed.
Title: Menelaus
Content:  Menelaus appears as a character in a number of 5th-century Greek tragedies: Sophocles' Ajax, and Euripides' Andromache, Helen, Orestes, Iphigenia at Aulis, and The Trojan Women.
Title: Pieris (mythology)
Content: Menelaus had ... by a female slave Pieris, an Aetolian, or, according to Acusilaus, by Tereis, he had a son Megapenthes" In Greek mythology, Pieris was one of the names given for the slave who was the mother, by Menelaus, of Megapenthes. Homer's Odyssey, and the geographer Pausanias, mention that Megapenthes was the illegitimate son of Menelaus, king of Mycenaean Sparta, by a slave, without naming her. But according to the mythographer Apollodorus: Other sources give other names for the slave who bore Megapenthes.

Question: Who is the mother of Menelaus?
Answer: Aerope.