Дисмас и Гестас
Yeshua Ha-Notsri is crucified together with Dysmas and Gestas. Gestas sings quietly a hoarse, senseless song, something about grapes. His head, covered with a turban, occasionally sways, and then the flies rise sluggishly from his face and settle on it again. Dysmas suffers more than the other two, he claws the ends of the crossbar with his nails, keeps his head turned towards Yeshua's post. "'Silence on the second post!". In the fifth hour of their suffering the threesome gets something to drink, and are then killed by the executionor with a spear.
In the gospels of the New Testament (Matthew, Mark, Luke and John) the names of the thieves who were crucified together with Jesus, are not mentioned. So how could Bulgakov know them? That's because there exist much more gospels than the four we know from the New Testament. In 367 the archbishop of Alexandria distinguished Gospels "inspired by God" and the so-called apocryphal gospels. His list of by God inspired books corresponds to the New Testament as it is known today. And most of the apocryphal texts were forbidden.
There are apocryphal gospels written by Judas, Thomas, Nicodemus, Philip, Bartholomew and much more, there's even one written by Maria Magdalena. This last one became famous by the Da Vinci Code, written by Dan Brown.
In the Gospel of Nicodemus, also called The Acts of Pilate because it is focussed on Jesus' Way of the Cross, the two names are mentioned. In Book IX:5 Pilate says: "Thy nation hath convicted thee as being a king: therefore have I decreed that thou shouldest first be scourged according to the law of the pious emperors, and thereafter hanged upon the cross in the garden wherein thou wast taken: and let Dysmas and Gestas the two malefactors be crucified with thee."
In christian tradition Dysmas, who was crucified at Jesus' right side, is often called the good thief, or even the good muderer. He asked for mercy and was saved. He could join Jesus in heaven. Gestas taunted Jesus about not saving himself and went to hell. The typical Russian orthodox crucifix reminds to it. There is a bottom slanting bar. It signifies that the thief on Christ's right chose the right path while the thief on the left did not.