Saints Boris (in baptism, Romanus) and Gleb (in baptism, David) were sons of Saint Vladimir the Great Prince of Kiev. When their father was near death in the year 1015, their elder brother Svyatopolk planned to kill his brothers in order to seize power over the entire kingdom. Boris and Gleb knew of their brother's plot, but they remembered the Lord's commandment, "Do not resist evil" (Matthew 5:39), and refused to raise an army to protect themselves.
Saint Boris was killed by assassins on July 24, 1015, when they found him praying for strength and for his brother Svyatopolk's salvation. When Saint Gleb received word that his brother and father had died, he wept for them, and was found by the assassins on September 5 of that year. But in the end he was stabbed by his cook, Torchin, and was left to die on the banks of the Smyadinya River.
The miracle-working relics of the brothers were placed in the Church of St. Basil in Vyshgorod in 1021. They were already being venerated as saints within 20 years of their deaths, as contemporary liturgical books show.
Saints Boris and Gleb are commemorated primarily on July 24, and also on May 2. They are called "Passion-Bearers," as they bore their suffering and faced death in a Christ-like manner.