Iceland issued in 1969 two stamps for the Centenary of Nordic Cooperation. Commemorating the centenary of the first postal Nordic co-operation and the 50th anniversary of the "Norden Association". Five commercial ships (Viking Ships) taken from five different silver coins, dated about the year 825, found at Björkö in Sweden https://en.wikipedia.org/wiki/Birka#Bjö ... gical_site
Iceland 1969 6.50/10 Kr sg?, scott? (The same design was used by Finland, Denmark, Sweden and Norway.)