Old country shown in newspaper, Siam (6)
I believe the answer is:
persia
'old country' is the definition.
(historical term for Iran)
'in newspaper siam' is the wordplay.
'in' indicates the answer is hidden within the clue.
'PERSIA' is hidden within 'newspaper siam'.
'shown' is the link.
(Other definitions for persia that I've seen before include "Praise be to ancient Iran" , "Former name of Iran" , "Old land" , "Old name for country at 25 Across" , "Old Iran" .)