Complex sentence: Following this turbulence, in 1771-1830, two claimants to the Catholic patriarchal seat made the Catholic Church unable to recognise neither until a unification of the them in 1830, the year from which the contemporary patriarchate traces an unbroken line.
Split into simpler sentences: Following this turbulence, in 1771-1830, two claimants to the Catholic patriarchal seat made the Catholic Church unable to recognise neither until a unification of both in 1830. This became the year from which the contemporary patriarchate traces an unbroken line.