I made a chart of the estimated ages of various characters in the Trojan War, using inforamtion from various sources. Multi-page explanation ahead:
Due to the multitude of sources that do not always agree, I will prioritise certain sources over others. First and foremost is textual evidence from the Iliad and Odyssey, next is any text summarising a lost epic (like the Cypria), then the works of the historian Pseudo-Apollodorus (as he had the most direct evidence), and finally any other classical sources.
Arguably the most important date when calculating this timeline is the Abduction of Helen, as told in the Cypria. Fortunately the Iliad explicitly says that at the time, the Trojan War had gone on for almost 10 years and was Helen’s 20th year in Troy. This places the abduction of Helen 10 years before the war. This is backed up by Apollodorus, who stated that two years after the abduction there was a failed attempt to attack Troy, which was eight years before the Trojan War properly started. So I will consider this a hard date to base other information on.
Placing the Oath of Tyndareus (aka the Suitors of Helen) is a bit harder, but given that several of the suitors were still quite young when the war started it can be assumed to be no more than a few years earlier. I placed it 12 years before the start of the war, assuming Helen and Menelaus had their daughter Hermione immediately after marrying (who was one year old when Helen was abducted). While Apollodorus states that Hermione was nine years old when Helen was abducted, though I am disregarding it because it would make everyone way too old and mess up other details.
Like most women of the time, Helen and Clytemnestra almost certainly married and had children as teenagers. By the time the war started, Clytemnestra had a daughter of young marriage age (Iphigenia at Aulis), presumably about 14. Assuming Clytemnestra had Iphigenia at 15, she and Helen would both be 29 when at the start of the Trojan War (or 17 during the Oath of Tyndareus).
Their brothers Castor and Pollux are a complication as they are almost always listed as Argonauts, which is described as being one generation before the Trojan War. This means that either a) they weren’t Argonauts or b) they weren’t twins of Clytemnestra and Helen. As I found far more myths stating the former, I assumed they were instead much older brothers (being about 14 during the Argonautica or about 44 when the war began).
Of all the Achaean leaders, Achilles has the most explicit age. Apollodorus states that he was nine when he was sent to Skyros, after the first attempt to attack Troy. This would make him 17 when the war began. Meanwhile Patroclus was old enough to be a suitor but young enough to have grown up with Achilles, which I interpreted as 24 when the war began.
Diomedes also has direct evidence, having ruled Argos for more than five years by the time the war began. As he became king at 14 after the Epigoni (10 years after Seven of Thebes) he would be 20 when the war began. This does have the consequence of him being a suitor aged 8, but children sent as suitors by their guardians wasn’t unhead of.
Odysseus is described as being of an older generation to many of the other leaders, though considering his father was alive at the end of the Odyssey he likely was about 40 or so when the war began. Assuming Penelope was betrothed to him aged about 14 (though they likely only married a few years after that), making her 26 when the Trojan War began.
Agamemnon and Menelaus were also described as older, though Menelaus was visibly younger than Odysseus. Assuming Agamemnon was 25 when he had Iphigenia and Menelaus was 20 when he married Helen, they’d be 39 and 32 respectively when the Trojan War began.
Nestor was the oldest of the leaders, having lived for three generations. I estimated this as him being about 70 when the war began. His son Antilochus was described as younger than Achilles, or about 16 when the war began (meaning he was a suitor aged four lol).
The only other Achaean leader with any evidence about his age is Telamonian Ajax, who was described by Antilochus as being a few years older than him in the Iliad, or about 21 when the war began. The rest of the leaders were likely between 25 and 42 when the war began, assuming they were between 13 and 30 during the Oath of Tyndareus.
For some of the parents, Laertes and Peleus were also Argonauts, so assuming they were about 30 then they’d be 60 when the war started. Anticlea was likely a teenager when she had Odysseus, or about 55 when the war started.
For the Trojans, Paris was a young adult when he abducted Helen (as per the Cypria), so he’d be 30 when the war began. Hector was likely a bit older (about 32), and Cassandra and Helenus were likely a bit younger (about 28). Aeneas was described as a younger peer of Paris and Hector (but still old enough to join Paris on his voyage to Sparta), or about 24 when the war began. Priam was likely similar in age to Nestor and Hecuba was likely about 15 when she had Hector (as he was the first of 19 children), making them 70 and 48 respectively when the Trojan War began. Andromache and Briseis were likely teenagers when the war began (with Briseis being older as she was already married), so roughly 15 and 17 respectively.
As stated before, Iphigenia and Hermione were about 14 and 11 respectively when the Trojan War began. Neoptolemus was of fighting age when Troy fell, so if Achilles had him very young he’d be about 3. Orestes was in his twentieth year (aka 19) during the Oresteia (which was before Menelaus returned to Sparta after voyaging for seven years), making him likely also 3 when the war began. Meanwhile Telemachus was an infant when Odysseus left, or about 1 year old when the war began (as it was likely many months between the two events).
Just remember that all information here is speculative and many of the exact figures are educated guesses (and I suspect all dates would be shifted by a few years either way), so feel free to disagree with any assertions I made. I mostly just made this because I thought it was interesting. Also gives some interesting insight to the relative ages and stuff (and definitely sheds light on some of the concerning ages during certain events). I am busy making a full timeline which includes the information here and numerous smaller myths with the same characters. I hope people found this (very long) post interesting!
