The origin of this Feast is explained in the Greek Horologion of 1897: “Because of the illnesses which occur during the month of August, it was customary at Constantinople to carry the Precious Wood of the Cross in procession throughout the city for its sanctification, and to deliver it from sickness.”
On the eve (July 31), the Cross was removed from the imperial treasury and placed it upon the Holy Table of the Great Church of Hagia Sophia (which is dedicated to Christ, the Wisdom of God). From August 1 until the Dormition of the Most Holy Theotokos, there was a procession throughout the entire the city, and then the Cross was placed where all the people could venerate it.
In the Russian Church this Feast is combined with the remembrance of the Baptism of Rus on August 1, 988. In the “The order of services for the holy, catholic, and apostolic Great Church of the Dormition,” which was compiled in 1627 by order of Patriarch Philaret of Moscow and All Rus, there is a similar explanation of the Feast: "On the day of the Procession of the Precious Cross there is a Cross Procession with the Sanctification of Water, for the enlightenment of the people, in all the towns and places."
Knowledge of the day of the actual Baptism of Rus is preserved in the Chronicles of the XVI century: “The Baptism of the Great Prince Vladimir of Kiev and of all Rus took place on August 1.”
In the current practice of the Russian Church, the service of the Lesser Sanctification of Water on August 1 takes place either before or after Liturgy. Because of the Blessing of Water, this first Feast of the Savior in August is sometimes called “the Savior of the Water.” Along with the Blessing of Water, there may also be a Blessing of Honey (thus it is also called “the Savior of the Honey),” because on this day, the newly-gathered honey is blessed and tasted.