It is considered a crucial event that stabilised the Uniate liturgy and organisation after this Church had managed to gain the upper hand among the Eastern Christians of the Polish-Lithuanian Commonwealth.
Many Orthodox Ruthenians, however, regarded that agreement as contemptible and rejected it outright, which led to a prolonged internecine strife among the Commonwealth's Eastern Christians and constituted one of the causes of the Cossack uprisings.
In the course of the seventeenth century, the Polish-Lithuanian Commonwealth lost control of Kyiv and the territories on the left bank of the Dnipro, inhabited by the Ukrainian Cossacks and nobles fiercely opposed to the Union of Brest.
[3] In the second decade of the eighteenth century the Uniate Metropolitan Lev Kyshka applied to Rome for permission to convene a provincial synod that would order the affairs of his Church and solidify its dominance among the Commonwealth's Ruthenians.
In the nineteenth century the Zamość regulations formed the basis of the Greek Catholic liturgical and organisational practices in Austrian Galicia, but critical voices continued to challenge them.