Raphael Holinshed, The Chronicles of England, Scotland and Ireland: Holinshed was a historian of the late 16th and early 17th centuries, widely read by his contemporaries. Although attributed entirely to holinshed, the Chronicles were actually a compilation of the works of several contemporary historians. The passages dealing with Cymbeline and Guiderius are sporadic, and Shakespeare took a great deal of liberty with them. The martial feats of Bealrius, Guiderius, and Arviragus, for example, are from an episode hundreds of years after Cymbeline but also detailed in Holinshed's work.

Boccaccio's Decameron is the source of the wager story. It occurs in Novel IX of the Second Day . . .

The prose tale of Frederyke of Jennen . . .

Other references (contemporary with or available to Shakespeare) to Cymbeline and related characters:

Spenser's Faerie Queene Book II, Canto 10, Stanzas 50-51

A Mirror For Magistrates