Question: What year did the polish brethren show up?
About the article "Protestant Reformation", section "Polish – Lithuanian Commonwealth".

Candidate passages:
Twenty years later Czechowic had moved from the Calvinist "Ecclesia Major" to the Unitarian "Ecclesia Minor", or Polish Brethren.
In doing so he adopted what was later to be known as the "Socinian" position, between Arianism, which taught the pre-existence of Christ and full Unitarianism which denied the virgin birth.
Czechowic believed that Jesus was human, but because he was born without sin, it was right to worship him.
Czechowic was in his mid-forties, of the same generation as Fausto Sozzini, Georg Schomann, Gregory Pauli, Krzysztof Morsztyn Sr., Pierre Statorius.
He has been described as the "Pope" of the Polish brethren, though this is something of an exaggeration - it is perhaps more that as a native Pole among so many German, Italian and French exiles he had more traction within the local brotherhood.
He adopted unconditional pacifism and opposed infant baptism and, because of the political obligations, the amassing of private property.
His attitude to Eve's sin was relatively progressive for the period.
Czechowic, like most of the Polish Brethren, was not supportive of the personal idea of Fausto Sozzini that baptism is not necessary for individuals who believe and who have grown up in Christianity, but Sozzini did not push his idea, and was generally accepted in the movement that later became known by his name. 
  Autobiographical "Testamentum ultimae voluntatis" (1684 in Amsterdam in "Bibliotheca antitrinitariorum" of Christopher Sandius Works.
Schomann drew up the first Socinian catechism (1574) of the Polish Brethren.
It was followed by that of Faustus Socinus himself.
Like another Polish Brethren writer Andrzej Wiszowaty he was cited by Voltaire 
In the Second Polish Republic, 1937, priest Karol Grycz-Śmiałowski recreated what he considered was a revival of the Church of Polish Brethren in Kraków.
In the People's Republic of Poland it was registered in 1967 as the Unity of Polish Brethren ("Jednota Braci Polskich").
Modern groups which look to the Polish Brethren include the Christadelphians and CoGGC.
Although Christadelphians had since their origins in the 1840s always looked for historical precedents, particularly to Arius, the group was unaware of closer precedents in Socinianism.
This changed with a series of articles in the community magazine during the early seventies subsequently published.
The Polish arm of the Christadelphians use the name Bracia w Chrystusie in conscious echo of Socinian precedents.
The Atlanta Bible College of the CoGGC also publish a Journal continuing research into the Polish Brethren and related groups. 
Janusz Jan Niemojewski (1531–1618) was a Polish nobleman, and theologian of the Polish Brethren. 
The Synod of Skrzynno 24 June 1567 was a synod between the Arians and Socinians among the Antitrinitarian Polish Brethren.
From 1550-1563 Calvinists and Arians had met together at the Synods of Pińczów, the final synod in 1563 marking the break between the Calvinist "ecclesia maior" and the "ecclesia minor" of the Polish Brethren.
A synod the following year at Piotrków Trybunalski in 1564, cemented the separation of Calvinists and Anti-Trinitarians.
At the anti-Trinitarian synod at Węgrów on December 25, 1565 Georg Schomann, Matthias Albinus and Gregory Pauli took positions against Arianism, the belief in the pre-existence of Christ, marking the beginnings of characteristic Socinian belief (although) Fausto Sozzini did not arrive in Poland till 14 years later in 1579.
The synod of Skrzynno was held at Skrzynno, Masovian Voivodeship, not Skrzynno, Łódź Voivodeship.
Several divisions among the Polish Brethren were visible but the parties adopted a resolution maintaining an external union based on a unitarian doctrine.