I was requested to post a thread about Finnish mythology for a while back, but what with one distraction and another, I partially forgot about it. However, I might try to remedy this laxness of mind now. I'll start with some geographical information, as the whole concept of Finno-Ugric peoples might be entirely new to many. If my writing gets harder to chew than a lorryload of styrofoam because of unfamiliar terminology, feel free to give me a poke and I'll edit it.
Furthermore, some very rudimentary knowledge of Norse mythology might be required, at least in the portions where I compare these two with one another. If something causes a cloud of question marks to spin around your head, don't hesitate to ask about it. 
I've talked about a smattering of odds and ends relating to this topic elsewhere on this forum, so I may well repeat myself occasionally. I'm using materials from Wikipedia whenever I deem them reliable enough. Scant as they are, this also helps in harvesting English-language texts available to everyone.
With the term Finnic, rather than Finnish, I refer to the Finno-Ugric peoples of the Scandinavian and Baltic areas plus those living in the Russian territories closest to the present-day Finland. Since I'm scarcely omniscient in this subject, I'll concentrate on 2-4 major topics: the Finns, the Saami, and the Estonians. Note that these Wikipedia links pertain to modern-day settings, and a good thousand years back, before the advent of Christianity, no clear national borders existed, and the habitat of Finnic tribes used to be much broader. Since then, many have become extinct, hence making it cumbersome to point out exact locations.
Finland lies between Sweden and Russia, and Estonia rises from the sea directly in the south. Simply put, Finland has a cold, ungenial climate, 4-6 months of permasnow during regular winters, and must endure the same polar twilight as Alaska. Even so, people have unceasingly lived here ever since the Stone Age.
Where exactly on the map?
Finnic peoples in Foreign Accounts
A careful reader can spot descriptions of Finnic peoples every now and then in old chronicles and Norse sagas. Oftentimes they, however, do not bear names equal to the contemporary inhabitants of Fennoscandia and some terms have an entirely diverse meaning. Some examples can be found in the following.
A helpful map: www.lib.utexas.edu/maps/historical/euro ... olbeck.jpg
Aestii, Ests, Estonians
Tacitus (c. 100 AD) says:
On the right shore of the Suevic sea dwell the tribes of the Aestii, whose dress and customs are the same with those of the Suevi (Swedes). They worship the mother of the gods; and as the symbol of their superstition, they carry about them the figures of wild boars. This serves them in place of armor and every other defense: it renders the votary of the goddess safe even in the midst of foes. -- They even explore the sea; and are the only people who gather amber, which by them is called Glese, and is collected among the shallows and upon the shore.
Wulfstan of Hedeby (c. 900 AD) says:
This country called Eastland is very extensive, and there are in it many towns, and in every town is a king. There is a great quantity of honey and fish; and even the king and the richest men drink mare's milk, whilst the poor and the slaves drink mead. There is a vast deal of war and contention amongst the different tribes of this nation. There is no ale brewed amongst the Estonians, but they have mead in profusion. --
It is also an established custom with the Estonians that the dead bodies of every tribe or family shall be burned, and if any man findeth a single bone unconsumed, they shall be fined to a considerable amount. These Estonians also have the power of producing artificial cold; and it is thus the dead body continues so long above ground without putrefying, on which they produce this artificial cold; and, though a man should set two vessels full of ale or of water, they contrive that either shall be completely frozen over; and this equally the same in the summer as in the winter.
The Kvens of Kvenland (also spelled Quens, Käens, Cwenas, Quenland, Kvenland, Quænland, called Sitones in Tacitus' Germania): somewhat comparable to the present-day Finns, they inhabited a prehistoric kingdom called Kvenland, Kainuunmaa, Kaland, or Kalevala which stretched across both sides of the Gulf of Bothnia. They had permanent villages, hill forts, agriculture, and, according to some speculations, a form of military.Adam of Bremen (c. 1100 AD) says:
We were told, moreover, that there are in this sea many other islands, of which a large one is called Estland. --They adore dragons and birds and also sacrifice to them live men whom they buy from the merchants. -- This island is said, indeed, to be very near the land of women --.
This likely refers to a matriarchal system among the Kvens (such a custom would've been an abomination unto the Romans). Later, this gave ground to the belief that the Land of Amazons could be found in Fennoscandia, fortified by a blatant mistranslation: kven hovers very close to the Germanic kvinna, kvenna (wife, woman). In the Kalevala (see the introduction later), the witch Louhi reigns as the sovereign mistress over her dominion locatable somewhere in this area or to the north of it. Even these days a local stereotype lives on about the ladies of this region: that they're loud, dominant, physically strong, and quick to anger. I speak from experience here, what with having had such a grandmother.Tacitus says:
Upon the Suiones (Swedes), border the people Sitones; and, agreeing with them in all other things, differ from them in one, that here the sovereignty is exercised by a woman. So notoriously do they degenerate not only from a state of liberty, but even below a state of bondage.
Ohthere of Hålogaland (c. 900 AD) says:
The Sweons (Swedes) have to the south of them the same arm of the sea, called Ost Sea; and to the north, over the wastes, is Cwenland; to the west-north of them are the Scride-Finnas, and to the west the Northmen. The Cwenas sometimes make incursions against the Northmen over these moors, and sometimes the Northmen on them; there are very large meres of fresh water beyond the moors, and the Cwenas carry their ships overland into the meres, whence they make depredations on the Northmen; they have ships that are very small and very light.
Possibly a very corrupted reference to berserkers or the local men wearing wolfskins upon their heads.Adam of Bremen says:
In this area there are also very many other islands, all infested by ferocious barbarians and for this reason avoided by navigators. Likewise, round about the shore of the Baltic Sea, it is said, live the Amazons. -- Some declare that these women conceive by sipping water. Some, too, assert that they are made pregnant by the merchants who pass that way, or by the men whom they hold captive in their midst, or by various monsters, which are not rare there. -- And when these women come to give birth, if the offspring be of the male sex, they become Cynocephali.
In the Norwegian language, the name Kven has long applied to Baltic Finns, rather than 'Finn', which means a person of Saami origin.
Chuds, suhnit, soomet, suomalaiset: Baltic Finns comparable to present-day Finns and Kvens, they inhabited Southern Finland and, according to some sources, sections of Estonia. Chudes in folklore.
Finns, Skrithifinns, Lapps, Lapponians: Various Saami tribes, see the Wikipedia link above.
NOTE: sometimes the denomination appears to point to Baltic Finns rather than Saami, there's some confusion over this in various sources.
I have not yet personally met any Himantopodes. Perhaps pollution and Soviet nuclear tests have finished them off. The passage however manages to describe seiðr magic to a certain point of accuracy.Adam of Bremen says:
On the confines of the Swedes and Norwegians towards the north live the Skritefingi, who they say, outstrip wild beasts at running. On the east, Sweden touches the Rhiphaean Mountains, where there is an immense wasteland, the deepest shows, and where hordes of human monsters prevent access to what lies beyond. There are -- Amazons, Cyclops, and those Solinus calls Himantopodes, who hop on one foot, and those who delight in human flesh as food. The king of the Danes told that a certain people [the Saami] were in the habit of descending from the highlands into the plains. They are small of stature but hardly matched by the Swedes in strength and agility. These people, it is said, are to this day so superior in magic arts or incantations that they profess to know what every one is doing the world over. Then they also draw great sea monsters to shore with a powerful mumbling of words and do much else of which one reads in the Scriptures about magicians.
Wikipedia knows to add:
Karelians, Kirjalaland, Biarmland, Biarmia, Bjarmians: names for Finnic tribes and places dwelling approximately in-between the Kola Peninsula and lake Ladoga.In 1835, scholarship draws a Balto-Finnic link to seid, citing the depiction of its practitioners as such in the sagas and elsewhere, and link seid to the practices of the noaidi, the patrilineal shaman of the Sami people. However, Indo-European origins are also possible.[8] Note that the word seita (Finnish) or sieidde (Sami) is a human-shaped body formed by a tree, or a large and strangely shaped stone or rock and does not involve "magic" or "sorcery;" there is a good case, however, that these words do derive ultimately from seiðr.
What to Read First
The Kalevala
The Kalevala (tr. 'Kaleva's Land', sometimes 'Land of Heroes') remains the best single source for Finnish mythology and a must-read for anyone interested in delving further into the topic. The long epic written in alliterative verse, proportionate to the Icelandic Eddas or Beowulf, was composed by Elias Lönnrot in the early 19th century from folk poetry collected in Karelia and other parts of Finland. Epical heroes and wizards fight against the evil forces of the witch of Pohjola, woo beautiful maidens, and venture on daring quests even into the pits of Tuonela (the netherworld) whence the hero can sometimes return only through bodily resurrection. A summarized description of the characters can be found here and synopses of the poems here.
Note: Lönnrot invented small portions of poetry to connect otherwise disjointed stories and sometimes picked up character attributes from a wealth of sources. The young warrior Lemminkäinen, for instance, is a blend of three or four different legendary heroes. Lönnrot furthermore assigned more humanlike forms to the leads: in the original myths Väinämöinen and his comrades are giants. More about that later.
English translation version 1 (public domain):
www.gutenberg.org/ebooks/25953
www.gutenberg.org/ebooks/33089
Version 2 (public domain):
www.gutenberg.org/ebooks/5184
www.gutenberg.org/ebooks/5185
Buy on Amazon (also other versions exist):
www.amazon.com/Kalevala-Epic-Finnish-Pe ... 192&sr=1-4
Wikimedia Commons gallery of Kalevala illustrations:
commons.wikimedia.org/wiki/Akseli_Gallen-Kallela
Kullervo speaks to his cursed sword:
https://upload.wikimedia.org/wikipedia/ ... alleen.jpg
Frescoes in the National Museum of Finland: Ilmarinen ploughs the adder-riddled field, the defense of Sampo
https://upload.wikimedia.org/wikipedia/ ... reskot.jpg
(I'll add more here if and when I find some other images online.)
A companion book (recommended by my English-speaking friend):
www.amazon.com/Kalevala-Mythology-Folkl ... 691&sr=1-1
Classical music adaptations by Jean Sibelius:
www.amazon.com/Sibelius-Kullervo-Sympho ... 924&sr=1-3
www.amazon.com/Sibelius-Finlandia-Karel ... 972&sr=1-3
Creation, Cosmology, Spirits
In Finnic mythology, the world was created from the egg of a water bird (often a pochard), the other half becoming the dome of the sky, the other the waters and land, while the yolk rolled off into the sky to assume the role of the sun. Several variations about the first living persons exist, but usually these included Ukko or Vanataat (a god of air or thunder) besides a Sea Giant (Ikuturso or Turisas) who mated with the maiden of air who, later (sometimes this 'trifling while' consists of 700 years) gave birth to Väinämöinen, the god of wisdom, poetry, and singing. He emerged from the waters as an elderly but powerful man, white-haired and bearded. In Estonian myths, at the beginning of all things Vanataat created the kalevid, giants, (ao. Väinämöinen, Ilmarinen, Lemminkäinen, Kaleva), who later helped shape and build the earth and heavens. The Estonian Ilmarinen forged the stars, and Väinämöinen, the original Forestall, wandered about the lands, causing tall trees and flowers to shoot up from the soil with his magical singing and kantele-playing. Giants, overall, were considered to be the first-ever inhabitants of the north: a race called Jatulit, Jiehtanasit or Kalevanpojat (means the same as the Norse Jötunn) populated the shores of the Gulf of Bothnia before the Saami. They were believed to have fashioned various megalithic stone constructions like hiidenkiukaat (barrows) or jatulinkirkot (neolithic monuments) and thrown massive rocks (hiidenkivi, kukkarokivi, originally transported hither and thither by glacial currents during the ice age) while contesting with one another.
According to the prehistoric cosmology, an axis mundi nailed to the Northern Star supported the cupola of the layered welkins, which, according to some poems, were six or nine (compare to the Nine Worlds in Norse myths). A giant fox running through the upper airs illuminated them with the aurora as it whisked its tail. In the furthest north was situated the center of the world, and there, right below the axis mundi, roiled the herculean whirlpool Kinahmi, a route down into Tuonela, the dominion of the dead. In the remotest south hid Lintukoto, the collective home of (migrating) birds. The Milky Way (F. Linnunrata, 'bird's track'), was understood to guide the flight of birds. Kuumet and kapeet (certain types of sky spirits) obscured and released the moon during eclipses.
Only traces of age-old Finnic beliefs relating to cosmology remain, but the alignments of celestial bodies must've once greatly affected rituals and the general goings-ons of the shamans or witches.
Origins, Guardian Spirits
The origin, the birth of any object or condition, whether it be a stone, tree, sickness, etc. and its true name were important in warding off evil or conjuring something for aid. For instance, if a snake had bitten someone, a part of the curing ritual consisted of reciting verses about the origin of the serpent. The same would apply to someone suffering from a sword wound; a blade is forged of iron, and hence one would reach out to the very birth of this metal. Apparently this logic made perfect sense to our forebears.
"Ukko, mightiest of Creators,
He, the God above in heaven,
From the Air the Water parted,
And the continents from water,
When unborn was evil Iron,
Uncreated, undeveloped.
"Ukko, God of realms supernal,
Rubbed his mighty hands together.
Both his hands he rubbed together,
On his left knee then he pressed them,
And three maidens were created,
Three fair Daughters of Creation,
Mothers of the rust of Iron,
And of blue-mouthed steel the fosterers.
"Strolled the maids with faltering footsteps
On the borders of the cloudlets,
And their full breasts were o'erflowing,
And their nipples pained them sorely.
Down on earth their milk ran over,
From their breasts' overflowing fulness,
Milk on land, and milk on marshes,
Milk upon the peaceful waters.
"Black milk from the first was flowing,
From the eldest of the maidens,
White milk issued from another,
From the second of the maidens,
Red milk by the third was yielded,
By the youngest of the maidens.
"Where the black milk had been dropping,
There was found the softest Iron,
Where the white milk had been flowing,
There the hardest steel was fashioned,
Where the red milk had been trickling,
There was undeveloped Iron.
"But a short time had passed over,
When the Iron desired to visit
Him, its dearest elder brother,
And to make the Fire's acquaintance.
"But the Fire arose in fury,
Blazing up in greatest anger,
Seeking to consume its victim,
E'en the wretched Iron, its brother.
. . .
Every person possessed a so-called guardian spirit (luonto), which has little to do with angels in Christianity. This was believed to be the ghost of an ancestor, emerged from the collective abode of the dead from beneath deep waters. A child received her luonto only after teething, before which she would've been especially vulnerable to the influence of vindictive spirits. If the luonto was particularly eminent, a person could experience an etiäinen. Also many places, including individual houses, stood in the protection of various wardens: väki (the powers of diverse groups of spirits: for instance veen väki, the powers of water spirits) and tomte/tonttu (a dwarvish or gnome-like creature, mayhap best known for protecting saunas or grainholds). Plants and animals furthermore boasted with their own ancestral gods or guardians, so-called emuu, the first father or mother or their kin. Höyheneukko (feather-mother) was the emuu of birds, Lemmes the emuu of alders, Kyllikki the emuu of stones in some folk poems.
The human soul (scarcely analogical with any Christian ideas either) was believed to comprise of several parts called sieluolento (soul-wight), some of which could reside outside the body. Luonto granted a person their luonne (character, personality), and itse was a form of shadow-soul, a mirror image of one's self. If a person lost one of their sieluolentos, he might fall grievously ill or elsewise become depressed. Upon death or birth, a soul-bird, usually a water fowl, brought or snatched away the parts of soul. A Finnic noita (witch, shaman) would--after falling into trance--send one of his sieluolento into the otherworlds to listen to the advice of ancestral spirits or invite them over to the physical world.
I'll post more if this stirs any interest.
So, (possibly) to come in non-specific order: rituals, customs, more about gods, spirits, and the worship of thereof, giant legends, important annual feasts, etc.
Ah well, I'll write a line about that too. 
But that's 
Curse you, life and other distractions.
