Complex sentence: However, existing sets of old Anchor Stones remained very popular within the international community; in 1979, the Club van Ankervrienden (Club of Anchor Friends) was founded in the Netherlands.
Split into simpler sentences: However, existing sets of old Anchor Stones remained very popular within the international community. In 1979, the "Club van Ankervrienden" ("Club of Anchor Friends") was founded in the Netherlands.