Three people, who are made of absolute win, have created a visualization of Zeus' affairs and the offspring that came from those unions, based on classical authors. You can click on the 'play' button below to get taken directly to the interactive map where you can explore for yourself.

I've spend a good bit of time on this intriguing creation yesterday, and I would like to share some of my findings. General findings first: for one, the people who created this--Ilaria Pagin, Viviana Ferro, and Elisa Zamarian--put a lot of time and effort into this. The schematic is easy to read, which is a huge bonus. I would have liked to have the authors listed by (approximate) date of publication instead of alphabetically, but that's just for my personal research purposes.

For me, the Hellenic authors are of greatest interest. I care about the time when they wrote what they wrote. Through them, the lives of the Theoi can be followed. While some of the Roman myths relate to the Theoi, most don't. In this case, they apply to Jupiter, not Zeus. They muddle the mythology of the Gods I worship. Because of this, I dilute from the diagram a list of authors of interest to my research, and exclude those who are not. 
  • Homer (Hómēros, Ὅμηρος) [c. 800/700 - c. 701/601 BC]
  • Hesiod (Hēsíodos, Ἡσίοδος) [c. 750 - c. 650 BC]
  • Aeschylus (Aiskhulos, Αἰσχύλος) [c. 525/524 BC – c. 456/455 BC]
  • Pindar (Pindaros, Πίνδαρος) [c. 522 – c. 443 BC]
  • Orphic Hymns [c. 600/500 - c. 500/400 BC]
  • Apollonius Rhodius (Apollṓnios Rhódios, Ἀπολλώνιος Ῥόδιος)  [c. 300 - c. 201 BC]'
  • Diodorus Siculus (Diodoros Sikeliotes, Διόδωρος Σικελιώτης) [c. 60 - c. 30 BC]
  • Strabo (Strabōn, Στράβων) [c. 64/63 BC – c. 24 AD]
  • (Pseudo-)Apollodorus (Ἀπολλόδωρος) [c. 201 - 300 c. AD]
  • Pausanias (Pausanías, Παυσανίας) [c. 201 - c. 300 AD]
  • Eustathius of Thessalonica (Eustathios of Thessalonike, Εὐστάθιος Θεσσαλονίκης) [c. 1115 – c. 1195/6 AD]
Note that Titus Flavius Clemens is missing; his works were about the Hellenic Gods, but placed in such a strong Christian light that, for the purpose of 'finding out that the Hellenes believed', I'm going to discount him for now. I have the same problem with Eustathius of Thessalonica, but because he references many Hellenic writers in a way that seems more focused on historic accuracy than Clemens, he's in. I have included only his quotes, not his own remarks. Nonnus of Panopolis is also out, not because he did not write about the Theoi, but because Hellenic myths from his time (around the first half of the 5th century AD) have been criticized for giving a misleading overview of genuine classical mythology.

This graphic is a great tool to gleam some understanding of the King of the Theoi. Especially when we start at the beginning. Hómēros came first, giving us Zeus' marriage with Hera and the birth of their daughter Eris, and their son Ares. Hómēros also records and affair with Demeter which results in the birth of Persephone, his marriage to Themis before Zeus married Hera, and the birth of his daughter Nemesis. Zeus may have fathered a child with Nemesis: the tragically beautiful Helene. Hómēros also makes note of Zeus' affair with Mnemosyne, Goddess of memory and remembrance, who happens to be Zeus' aunt. From their union came the nine Muses. 

In Hómēros' version of the birth of Aphrodite, she is the child of Zeus and Dione, a Titan and Zeus' cousin. With the moon Goddess Selene, Zeus had Pandeia, Goddess of the full moon, and Dionysos was born from a union with Thyone (Semele). With Maia, Zeus had Hermes, and with Leto the Divine archers Artemis and Apollon. Homeros also records a union with the harpy Podarge, from which came Xanthus and Balius, the immortal horses of Achilles. With the human queen Leda, Zeus had Kastor and Polideukes. Leda also fostered Helene.

Hómēros has a few more affairs on record. From a union with Laodamia (sometimes called Deidamia), daughter of Bellerophon, came Sarpedon, one of the great heroes of Troy. With the human princess Danae, Zeus fathered Perseus, and with the princess Hyria, he fathered Amphion and Zethos.

Hesiod adds to Zeus' relations and children Hebe, Hēphaistos, and Eileithyia by Hera, and Limos by Eris. Through Themis, he grants paternity to Zeus for the Horai and Moirae. Through Metis--a new lover in the list, but listed as His first wife--Athena is born. Hesiod also adds Eurynome to Zeus' list of lovers, and adds three children: the Kharites. Another four newcommers are Elektra and her son Dardanos, Aegina and her son Aikos, Io and her son Epaphus, and Kallisto and her son Arcas.

Another new affair of Zeus is recorded by Hesiod as Thyia, daughter of Deukalion, with whom Zeus has two strong sons: Makedon and Magnes. Pandora II, grandchild of Pandora is also given as a lover of Zeus. The child that resulted from that union is Graecus. Hesiod also adds Calyce and Cassiopea to the list. With Calyce, Zeus had Aethlius, and with Cassiopea, Atymnius. From Hesiod also come Alcmene and her son Hēraklēs, and Europa, with whom he had three children: Rhadamanthys, Sarpedon and Minos.

Aeschylus offers a retelling of some of the affairs (most notably Maia, Europa and Io) but does not add new affairs or children to the list. Pindar does. He adds a new affair with Aegina, which results in the birth of Damocrateia and Aiakos, and through Protogenia, he adds Opus to the list of Zeus' children. Of note in Pindar's writing is that he gives parentage to Zeus of the Horai, but not the Moirae, and of Kastor, but not Polideukes.

The Orphic Hymns add a new lover and two children to the list: his daughter Persephone, who grants him two children: Zagreus, the 'first-born' Dionysos and Melinoe, frightful Underworld Goddess who presides over the propitiations offered to the spirits. Apollonius Rhodius adds two new affairs and an equal amount of children to the list: Orchomenos through Isomoe, and Myrmidon through Eurymedousa. Apollonius also grants paternity of both Dioscuri to Zeus.

Unlike his predecessors, Diodorus Siculus describes only one child by Persephone (Zagreus), but add one to his union with Elektra: Harmonia. He also adds a new lover: the nymph of Samothrace, with whom Zeus has a son named Saon. New to the list are also the demi-Goddess Karme and the nymph Himalia. With Karme, he has one of his few female offspring: Britomartix, the virgin Goddess of hunting and netting. Kytos, Kronios and Sprataios are listed as the sons of Himalia and Zeus. 

Strabo adds three new affairs and nine children to the list: Tántalos, though his mother Plouto, the seven daimons of the Korybantic dance through Kalliope, and Olenus through Anaxithea. The last of these is attributed by Strabo to Hómēros.

(Pseudo-)Apollodorus gives a great many affairs, most of which reach back to older writers. He makes a few adaptations to the list: Eris is not listed as a child of Zeus through Hera. Through Themis, Zeus only fostered the Horai, Styx is given as the mother of Persephone (which gives the myth about Her abduction by Hades a whole other spin I must come back to some day), Leda is--like in the writings of Hesiod--the (foster) mother of Kastor, Polideukes and Helene, and he gives a second child from Zeus' union with Eurynome: the river God Asopos. 

New on the list are Hekate through the Titan Asteria, and Argos and Pelasgos through Niobe. Note that this is a different Niobe than the Niobe who was punished by Leto for hubris committed against Her. Also new is Zeus' lover Elare, who gifted Zeus the Phokian giant Tityos.

The notable absences by Pausanias first: Hebe, Eris and Haphaestus are not amongst Zeus's children, and neither is Asopos through Eurynome. Helene is not listed as a child of Zeus, and neither are Rhadamanthys, Sarpedon and Minos by Europa, but he does make her the mother by Zeus of Alagonia and Carnus. Also new is Agaedistis through Gaea, although the original text spoke only of a 'Sky-father', and Ouranos would be much more logical. Another new child is Megarus by the Sithnis Nymph. 

Eustathius of Thessalonica is last on the list, but gives us references from Hómēros: through Eustathius, Hómēros describes an affair with the mortal woman Maera, from which a son came forth: Locrus. In the same way, we learn of Euryodeia and her son Arcesius.

Please note that I have only listed missing children where another of the children was obviously admitted. Most unions are only listed by one to three writers. More unions can be found in the myths told by the writers I have omitted.

Which conclusions can we draw from this listing-by-date? For one, the oldest myths are also the ones that are most famous today. They have been retold (and sometimes rewritten) by a variety of classical authors, and they form a basis for worship. Especially Hesiod and Hómēros have had this influence. The newer the writings get, the more 'one shot'-affairs are added to Zeus' history. This speaks of a distinct need or trend within the Hellenic people(s)--although these myths were probably localized!--which led to the birth of a new Divine child within that community, or as an example from another place. Harmonia is a good example for this as her domains include harmony and concord, and She gives a counterbalance to Eris, another of Zeus' children, but one much older. Tántalos, and his punishment in the Underworld, is another example.

Regardless of dating, the diagram gives a fantastic overview of the values and events of life that meant the most to the ancient Hellenes, and it is a roadmap to the birth of the Immortals--from Chaos all the way down to the nymphs and heroes.

I would greatly encourage anyone interested in Hellenic mythology to spend some time with this diagram. It's a wonderful tool to make sense of the genealogy of the Theoi. Remember, though, that there are often other, non-Zeus, versions of the myths which offer an entirely new perspective. This shows once more that mythology most likely developed locally, from common source material, and was then spread out by travelers or writings. Some myths or Gods existed already, and were adopted into the pantheon, making for loose ties and conflicting mythology. Aphrodite is a good example, as Her worship began with a cult of Astarte in Phoenicia. Aphrodite--to me--is Her own Goddess, separate from Astarte, but Her adoption was not without conflicting mythos. Here, she is born from Zeus, but there are myths--mostly by or based on Hesiod--which set Her paternity with Ouranos.

Enjoy this lovely creation!