Dionysius of Radonezh was the archimandrite of the Trinity-Sergiev Lavra during the Time of Troubles, the period of dynastic crisis, famine, and foreign invasion that beset the Russian lands in the early seventeenth century. Born around 1570 in the city of Rzhev and named David Zobninovsky in the world, he served as a novice and afterward headed the Staritsky Dormition monastery before being made archimandrite of the Trinity-Sergiev Lavra from 1611. In that office he became the foremost helper of Saint Hermogenes, Patriarch of Moscow, in the effort to deliver Russia from the Polish-Lithuanian occupation.
His tenure was marked by extensive works of relief amid the suffering of the war years. Near the monastery he opened a house and hospice for those injured and left homeless by the Polish-Lithuanian incursion, and during a famine he directed the brethren of the Lavra to subsist on oat bread and water so that the wheat and rye bread might be reserved for the sick. Together with the monastery's steward, the monk Abraham Palitsyn, he wrote in 1611-1612 to Nizhni-Novgorod and other cities urging them to send fighting men and money for the liberation of Moscow, and he wrote also to Prince Demetrius Pozharsky and to the military leadership, pressing them to hasten the campaign.
In his later years Dionysius undertook the correction of liturgical books, work that brought upon him an unjust trial. Engaged in 1616 in revising the Book of Needs by comparison with ancient Slavonic manuscripts and Greek editions, he was accused of heresy by those responsible for the errors he had identified, and at a Council in 1618 he was deposed and imprisoned at the Novospassky monastery. He bore this confinement with patience until 1619, when the Jerusalem Patriarch Theophanes and the newly returned Patriarch Philaret secured his release and his exoneration. He reposed on May 12, 1633, and was buried in the Trinity-Sergiev Lavra, where his veneration was established soon after his death.