During the years of the Quadrennial Diet Berek, who had given up his position with Masalski, and had married in the meantime, lived in Praga, a suburb of Warsaw. In the atmosphere of patriotic excitement, the vague impressions which his contact with the Polish nobility and his foreign travels had left upon his mind came to maturity. The heroic figure of Kosciuszko and the siege of Warsaw gave these vague sensations a concrete form. He realized that it was his immediate duty to fight for the freedom of the country, for the salvation of the capital, where Poles and Jews were equally shut off and cooped up by the hand of the enemy. Now was the time to prove that even the stepchildren of the nation knew how to fight in the ranks of her sons, and that they deserved a better lot. Accordingly, in September, 1794, at the very height of the siege, Berek Yoselovich, conjointly with Joseph Aronovich (son of Aaron), a fellow-Jew of like mind, applied to Kosciuszko, the commander-in-chief, for permission to form a special regiment of light cavalry consisting of Jewish volunteers. Kosciuszko immediately complied with their request, and announced it joyfully in a special army order, dated September 17, extolling the patriotic zeal of the originators of the plan, "who remember the land in which they were born, and know that its liberation will bestow upon them [the Jews] the same advantages as upon the others." Berek was appointed commander of the Jewish regiment. An appeal was issued calling for recruits and for contributions towards their equipment. Berek's appeal to his coreligionists was published in the official "Gazette" of Warsaw on October 1. It was written in Polish, though couched in the solemn phraseology of the Bible: Listen, ye sons of the tribes of Israel, all ye in whose heart is implanted the image of God Almighty, all that are willing to help in the struggle for the fatherland.... Know ye that now the time hath come to consecrate to this all our strength.... Truly, there are many mighty nobles, children of the Shlakhta, and many great minds who are ready to lay down their lives!... Why then should we who are persecuted not take to arms, seeing that we are the most oppressed people in the world!... Why should we not labor to obtain our freedom which has been promised us just as firmly and sincerely as it has been to others? But first we must show that we are worthy of it.... I have had the happiness of being placed at the head of the regiment by my superiors. Awake then, and help to rescue oppressed Poland. Faithful brethren, let us fight for our country as long as a drop of blood is left in us! Though we ourselves may not live to see this [our freedom], at least our children will live in tranquillity and freedom, and will not roam about like wild beasts. Awake then like lions and leopards!