Prokop, in 1434, embraces the more militant, antifeudal, peasant-worker (Taborite) branch of the Hussite movement, who in 1420 had given the biblical name of Tabor (Czech: Tábor) to their fortified settlement south of Prague.

Like their more moderate coreligionists, the Utraquists, they are strict biblicists and insisted on receiving a Eucharist of both bread and wine, though they deny transubstantiation and the Real Presence.

Nicholas of Pelhrimov, first bishop of the Taborites, heads an independent church that has replaced Latin with Czech in the liturgy, allowed married clergy, and rejected all the sacraments except Baptism and the Eucharist.

The Taborites' military campaigns and their destruction of churches, which had taken place under the leadership of Prokop the Lesser and the late Jan, Count Zizka, have aroused widespread animosity.

The Sirotci ("Orphans"; German: Waisen), officially Orphans' Union, are followers of a radical wing of the Hussites in Bohemia.

This force, founded in 1423 originally under the name Lesser Tábor, consists mostly of poorer burghers and some members of lower aristocracy, who had joined with and the eastern Bohemian Hussites, the so-called Orebites (Orebité).

After Žižka's death in 1424, the "orphaned" combatants adopted their new name.

From 1424 till 1428 they had been led by the priest Ambrož of Hradec, subsequently by another priest, Prokop the Lesser.

Hejtman Jan Čapek of Sány had been elected as their military commander in 1431.

When, after a brief peace following the convening of the Council of Basel, a united Utraquist and Romanist force from the old part of Prague seizes control of the more radical “new town,” Prokop Holý seeks, with the aid of Prokop the Lesser, to regain it but both generals are killed, together with other Taborite leaders, in at the ensuing Battle of Lipany on May 30, 1434.

As a consequence of the battle, the Taborite army is markedly weakened, and the Orphans virtually cease to exist as a military force.