They were published in book form, although not at Shakespeare's request or even with his knowledge in some cases. These books, even though they were printed almost 400 years ago and in some cases more than 400 years ago, still exist and can still be read. Thank God they were not only available as Kindles or some such rapidly obsolescent format.
griots
There is no written history of them. Everything was passed down through history verbally.
Timeline
History in West Africa through folktales passed down by the village griot.
It is passed through the genes of the mother or it is in their family history
The "unwritten Constitution."
Now I'm no expert but I'd say the history was passed down through generations.
Shakespeare's Sonnets were first published in 1609, by the London printer Thomas Thorpe. Sonnets 138 and 144 had appeared earlier, in the 1599 anthology The Passionate Pilgrim. The fashion for sonnets lasted from about 1580 until the very early 1600's - and for those twenty years sonnets were as cool and hip as rap is today. So by publishing in 1609, Shakespeare's sonnets had missed the boom years. But there are many references to sonnets written by Shakespeare much earlier than this (and we can see from the subject matter of many of the sonnets that they must have been written long before they were published). So it looks like Shakespeare's sonnets were originally passed round by hand, and only published as an afterthought (after Shakespeare had already become the most famous living playwright).
Several hurricanes have passed through Rhode Island in the early 21st century. In 2014, it experienced some of the coldest temperatures on record in its history.
Stories and personal histories passed down through a close collection of people, such as a family or tribe. Official history pertains to larger matters, folk history to everyday life within the clique.
Ethnic groups throughout Africa preserve their histories by maintaining a strong oral and written history or storytelling, through which cultural history and folklore is passed down through the generations.
Medical history can have a huge effect on exercise and training fitness can be inherited training can only be done to the level passed through the generations.