Between Battles at Thebes
Some time before the Trojan War, King Oidipous [Oedipus] of Thebes had two sons named Eteokles [Eteocles] and Polyneikes [Polynices] who had an agreement to share the throne of Thebes with each other. When they couldn't agree any more about this and Eteokles held control of the city, Polyneikes, with the help of six allies, besieged Thebes in a bloody conflict which ended in the deaths of both the quarrelling brothers as well as all six of Polyneikes' allies except one. The contest between Eteokles and Polyneikes came to be known as the war of the Seven Against Thebes.
King Adrastos [Adrastus] of Argos, the only one of the Seven to survive, later mobilised the sons of the Seven (his own son included among them), the so-called Epigonoi [Epigoni], in a new attack on Thebes. The enterprise of the Epigonoi took place ten years after the expedition of the Seven, and the sons succeeded where most of their fathers had perished.
Between a Duel and a War
Hyllos [Hyllus] was the son of Herakles and Deianeira. After Herakles' death, Hyllos killed Herakles' enemy Eurystheus in battle. After this battle, Hyllos led his many brothers, the sons that Herakles had had with numerous women, in a bid to conquer Peloponnesos [Peloponnesus], which they saw as their birthright. Atreus, whose father Pelops had conquered Peloponnesos and named it after himself, was the prominent ruler in the region at the time. Atreus' sons Agamemnon and Menelaus would later become the leaders of the Greek expedition against Troy.
Atreus struck a deal with the Herakleidai, "Sons/Descendants of Herakles," in which they would decide the contest by single combat. The Herakleidai would choose a champion to fight on their behalf and if he was defeated, they would withdraw their claim to Peloponnesos for a period of fifty years thenceforward. Hyllos was the selected champion from among Herakles' sons. He fought against King Ekhemos [Echemus] of Arkadia [Arcadia] and was killed. The Trojan War is supposed to have begun ten years after the death of Hyllos.
The Death of a Prophet
A few generations later Hyllos' death, a seer named Karnos [Carnus] was killed by Hippotes for his frenzied prophecies which seemed to be unfavourable to the mission of the Herakleidai. Hippotes was the son of Phylas, son of Antiokhos [Antiochus], son of Herakles. For this slaying, an oracle commanded the Herakleidai to banish Hippotes for ten years, which they did. The details of that story can be found in Apollodorus' Bibliotheka 2.8.3.
Between Wars Among Ionians
Five generations after the time of Hyllos, two groups of Ionians fought over the island of Samos. One group had been led there by Hyllos' descendant Prokles [Procles], whose son Leogoros ruled the island afterwards. War broke out between Leogoros and Androklos [Androclus], a descendant of King Neleus of Pylos. (Neleus had been killed by Herakles.)
Androklos was the leader of another group of Ionians from Ephesos [Ephesus], and they expelled Leogoros and his Ionians from Samos. Leogoros fled to the mainland with his people but ten years later they came back and returned the favour, removing the Ephesian Ionians from the island.
The Misadventures of Young Helen
The Trojan War was sparked off when Queen Helen of Lakedaimon was abducted or seduced by Prince Paris of Troy. This was actually the second time that an abduction of Helen had precipitated a war. When Helen was still a child she was kidnapped by King Theseus of Athens, who kept her, under the care of his mother Aithra [Aethra], in the Attic town of Aphidnai.
Helen's two brothers eventually found her and, in their outrage at the kidnapping, sacked Aphidnai and would have destroyed Athens as well if Menestheus, a relative of Theseus, hadn't intervened so convincingly that they not only spared Athens but also made Menestheus the city's king in Theseus' stead. (Theseus was preoccupied in the Underworld at the time. Meanwhile Aithra became Helen's slave.)
Apollodorus says that Helen was twelve years old when Theseus stole her away. Diodorus Siculus, on the other hand, in his Bibliotheka Historika 4.63.2, says that the Lakedaimonian princess "was only ten years of age" at the time.
According to Euripides' tragedy Andromakhe, at the end of the Trojan War, Neoptolemos [Neoptolemus] took Hektor's [Hector's] widow Andromakhe [Andromache] as his prize from among the spoils. He took her with him to Thessaly where he treated her well and she bore him a son. After ten years in this relationship, he married Hermione, the daughter of Menelaus and Helen. Much mischief ensued as a result of Hermione's jealousy of Andromakhe.
Similarly, according to Euripides' tragedy Medeia, Iason [Jason] and Medeia had lived happily as husband and wife in Korinthos [Corinth] for ten years before the city's king Kreon [Creon] offered Iason the hand of his daughter Glauke in marriage, on condition that he dissolve his marriage to Medeia and banish the two sons they had had. This led to the painful death of both Kreon and Glauke.