The Vikings, according to Viking Sagas, also made some raids into Tavastia. Here is an account of Olav the Holy raiding the coast. This may be either in Tavastian or "Finnish" territory:
"Then he (Olav) sailed to Finland, landed and pillaged there, but all of the locals escaped into the forests and took all their possessions with them away from the area/region. The king ventured far inland and through some woods; there were valley regions called Herdalarna. They took some property, but no men (Slaves? Prisoners?). When evening drew near, the King began his way back to his ships. But when they returned to the woods, they were confronted by men from all sides, and harrassed and shot at fiercely. The King told his men to take cover/protect themselves. But before they could get out of the woods, he had lost many men and several were wounded. He arrived at the ships in the evening. In the night, the Finns created a great storm with their witch-craft. But the king ordered to lift up the anchor and raise the sails, and they travelled along the coast during the night. The King's good luck was then, like so often, more effective than the witch-craft of the Finns. They managed to sail along the coast of Balegard and then out to sea. But a band of Finnish warriors followed them on land as the king sailed along the coast." ~http://www.allempires.com/article/index.php?q=Viking Age FinlandThe Finns have been known for their ability to raise fog, stop blood flow in wounds and singing people to sleep.
With magical time in mind you might want to check out this book: "The Magic Songs of the Finns". http://www.paganarchive.com/magic-songs-of-the-finns.html
"Since the time immemorial the Finns have used incantations, or Magic Songs. It's unknown when or how this tradition of magic first came to be, but already in pre-historical times they were widely used in all areas of life. The 639 spells and charms contained in this book were collected in the 19th century from the rural areas of Finland and Karelia, shortly after which this old esoteric tradition became extinct. They were first published in year 1880, and translated into English in 1896 as a part of larger folkloristic study, but have never before been published as an independent work."THE MAGIC SONGS OF THE FINNS.
1. Preliminary Formula
2. Defensive Measures
3. Against Envy
4. Vengeance Formula
5. To Discover the Cause
6. Reparation for Harm
7. Against Inflammation and Angry Symptoms
8. Expulsion Formula
9. Posting Formula
10. Pain or Sickness Formula
11. Reproaching Formula
12. Falling into Ecstasy
13. In Distress
14. Boasting Formula
15. To Still Violence
16. Menacing Formula
17. Exorcisms
18. To Make Fast
WORDS OF HEALING POWER.
19. For Stings of Wasps, Gadflies and other Insects
20. For Sickness caused by Elf-shots, sudden Strokes, etc.
21. For the Toothache
22. For Wounds caused by Hiisi
23. For Whooping Cough
24. For Injuries caused by Kalma
25. When torn by a Bear or a Wolf
26. For Contusions from a Stone
27. For Syphilis
28. To remove Tumours, Abscesses, Boils
29. For Snake Bites
30. For Gout or Heartburn
31. For cutting off Excrescences
32. For Contusions or Lesions
33. For the Hiccough
34. For Sprains
35. Against Nightmare
36. For Frostbite
37. For Stitch or Pleurisy
38. For Contusions from Trees
39. For Cancer or Whitlow
40. For Injuries from Iron
41. For Rickets, Atrophy
42. For Injuries caused by Spells
43. Against the Plague
44. For Thrush
45. For Pain in the Eye from Particles of Chaff
46. For Disease in the Eye
47. For a Lizard's Bite
48. For Laceration by a Wolf
49. For the Pains of Child-birth
50. For the Itch
51. For Skin Eruption
52. For Burns
53. For Scalds
54. For Injuries from Copper
55. For Hemorrhage
56. For Dropsy
57. For Cough
58. For Colic
FORMULAE.
59. Divination Formula
60. For a Bite from a Horse
61. To make a Horse stand still
62. Against Mice
63. Against Spiders
64. For a Cross-bow Man
65. For a Best Man
66. Against Grubs, Slugs, etc.
67. For catching Hares
68. For Fishing
69. Against Bears
70. To protect Cattle
71. A Spear Charm
72. For Dogs
73. For taking Ermines
74. To make Yeast rise
75. To charm Snakes
76. Court of Justice Charm
77. For Sheep
78. For Bathing Children
79. To quiet a Child
80. To excite Love
81. To alienate Love
82. To take Redstarts
83. For Fowling
84. For making an Artificial Decoy Bird
85. Against Bugs
86. Against the Cowhouse Snake
87. For making Vapour
88. A Milk-charm
89. Hunting Charm
90. Against Forest Fires
91. An Ale Charm
92. For catching Squirrels
93. Against Sharp Frost (Pakkanen)
94. A Snake Charm
95. Against Rust in Corn
96. Gelding Charm
97. Frog Charm
98. To drive away Rain
99. On going to the Wars
100. To exorcise Wolves
101. Charm to recite over Salt
102. For Health
103. Against Cockroaches
104. To lay the Wind
105. To lay a Whirlwind
106. To be recited over Water
107. For a Journey by Water
108. Trap Charm
109. Ointments
PRAYERS.
110. In the Morning
111. Treasure Seeking
112. Against Elf-shots
113. Against Wasps
114. Against Toothach
115. For Horses
116. When Gored by an Ox
117. At a Bridal Procession
118. For catching Hares
119. Against Cabbage Grubs
120. For Fishing
121. Bear Hunting
122. Against a Bear
123. To Benefit Cattle
124. At the Assizes
125. To incite a Dog
126. To silence a Dog
127. When Shooting Rapids
128. When in Great Pain
129. To Charm away Strumous Swellings on the Neck
130. While Sowing
131. To Stupefy a Snake
132. To Increase the Yield of Milk from Cows
133. To excite Love
134. To Wean a Heart from Another's Love
135. When Excising Superfluous Flesh
136. For Catching Birds
137. On Gering to Bed
138. Starting on a Journey
139. Hunting in the Forest
140. For Sprains, Injuries of the Bone or Sinews
141. When Butted by a Ram or a He-goat
142. Brewing Ale
143. For Good Luck
144. Squirrel-Hunting
145. Against Nightmare
146. Against Swellings and Scab
147. Against very Sharp Frost
148. For Catching Reindeer
149. For Pleurisy or Stitch
150. To Throw a Spell over a Gun
151. Setting Traps
152. For a Good Sleighing Road
153. For Catching Foxes
154. Against Injuries from Spells
155. For Trapping Sea-otters
156. To Drive away Rain
157. When Charming the Sick
158. Castration
159. Preparing a Bandage
160. Against Bits of Chaff, etc., in the Eye
161. For the Pigs
162. In War Time
163. Preparing for War
164. To Make Snow-skates
165. Against Incantations
166. For the Pains of Child-birth
167. Setting Up House
168. For Skin Eruptions
169. For a Healing Bath
170. For Making Edged Tools
171. Against Damage from Fire
172. To Bewitch Fire
173. In Making an Offering
174. To Recover Stolen Property
175. To Guard against Thieves
176. When on the Look-out
177. To Staunch Blood
178. When Travelling by Water
179. To Fortify Water
180. Against an Enemy at Sea
181. When Using Salves
182. For a Good Crop
ORIGINS OR BIRTHS.
183. The Origin of Wasps
184. Of Snails
185. Of the Tooth-worm
186. Of the Pike
187. Of the Horse
188. Of the Elk
189. Of Ague
190. Of the Seal
191. Of Men
192. Of the Cabbage-worm
193. Of the Bear
194. Of Courts of Law
195. Of the Cat
196. Of Stone
197. Of Cancer or Whitlow
198. Of the Dog
199. Of the Birch
200. Of the Raven
201. Of Swelling on the Neck
202. Of the Viper
203. Of the Snake
204. Of Flax
205. Of the Cowhouse Snake
206. Of the Earth-elf or Skin Eruption
207. Of the Sorcerer (noita)
208. Of Arrows
209. Of Ale
210. Of Sharp Frost
211. Of Stitch or Pleurisy
212. Of Trees
213. Of Cancer
214. Of Iron
215. Of Rickets, Atrophy
216. Of Injuries caused by Spells
217. Of Rust in Corn
218. Of Scab
219. Of the Pig
220. Of Particles of Chaff in the Eye
221. Of the Lizard
222. Of the Wolf
223. Of Salt
224. Of the Oak
225. Of the Titmouse
226. Of Fire
227. Of Copper
228. Of Water
229. Of a Boat
230. Of a Net
231. Of Brandy
232. Of Salves
233. Of Gripes, Colic, Constipation http://www.paganarchive.com/magic-songs-of-the-finns.html
"Love, Light and Joy!"Niina"