Strands of stories involving Republican Spain (6)
I believe the answer is:
fibres
'strands' is the definition.
'stories involving republican spain' is the wordplay.
'stories' becomes 'fibs' ('fib' can be a synonym of 'story').
'involving' indicates putting letters inside.
'republican' becomes 'r' (abbreviation).
'spain' becomes 'e' (abbreviation for Espana).
'r'+'e'='re'
'fibs' placed around 're' is 'FIBRES'.
'of' acts as a link.
(Other definitions for fibres that I've seen before include "Threadlike substances" , "thin strands or threads" , "Long thin substances, threads" , "Filaments" , "Threads or tendrils" .)