You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Szlachta

Context:
The Orthodox nobles' rights were nominally equal to those enjoyed by Polish and Lithuanian nobility, but there was a cultural pressure to convert to Catholicism, that was greatly eased in 1596 by the Union of Brest. See for example careers of Senator Adam Kisiel and Jerzy Franciszek Kulczycki.

Question:
What social pressure was pressing down the people?

convert to Catholicism