Reliques

 "The Reliques contained one hundred and eighty ballads in three volumes with three sections in each..

 It contains such important ballads as "The Ballad of Chevy Chase", "The Battle of Otterburn", "Lillibullero", "The Dragon of Wantley", "The Nut-Brown Maid" and "Sir Patrick Spens" along with 

ballads mentioned by or possibly inspiring Shakespeare, several ballads about Robin Hood and one of the Wandering Jew. 

https://en.wikipedia.org/wiki/Reliques_of_Ancient_English_Poetry

The claim that the book contained samples of ancient poetry was only partially correct

. The last part of each volume was given over to more contemporary works—often less than a hundred years old—included to stress the continuing tradition of the balladeer. 

The collection draws on the Folio and on other manuscript and printed sources, but  

in at least three cases anonymous informants, "ladies" in each case," contributed oral poetry known to them.  

 

https://en.wikipedia.org/wiki/Percy_Folio 

"The Percy Folio is a folio book of English ballads used by Thomas Percy to compile his  

Reliques of Ancient English Poetry. 

Although the manuscript itself was compiled in the 17th century, some of its material goes back well into the 12th century. 

It was the most important of the source documents used by Francis James Child for his 1883 collection

 The English and Scottish Popular Ballads."  

"Those who owned the manuscript before Percy did not treat it well;

 its owners had probably regarded its Middle English and border dialect as

 incomprehensible and worthless. 

 When Percy first came across the manuscript, in the house of its former owner Humphrey Pitt at Shifnal, Shropshire, 

pages were being used by his housemaids to start fires. " 

The handwriting in the manuscript appears to be the same throughout and bears some similarity with that of Thomas Blount