Many scholars consider Rublev's Trinity the most perfect of all Russian icons and perhaps the most perfect of all the icons ever painted. The work was created for the abbot of the Trinity Monastery, Nikon of Radonezh, a disciple of the famous Sergius, one of the leaders of the monastic revival in the 14th-century Russia. Asking Rublev to paint the icon of the Holy Trinity, Nikon wanted to commemorate Sergius as a man whose life and deeds embodied the most progressive processes in the late 14th-century Russia.
From the earliest times, the idea of the Trinity was controversial and difficult to understand, especially for the uneducated masses. Even though Christianity replaced the pagan polytheism, it gave the believers a monotheistic religion with a difficult concept of one God in three hypostases -- God the Father, God the Son, and God the Holy Spirit. Not only the uneducated population but many theologians had difficulties with the concept of the triune God; from time to time, a heretical movement, like Arianism, questioned the doctrine, causing long debates, violent persecutions, and even greater general confusion. Trying to portray the Trinity, but always aware of the Biblical prohibition against depicting God, icon painters turned to the story of the hospitality of Abraham who was visited by three wanderers. In their compositions, icon painters included many details -- the figures of Abraham and Sarah, a servant killing a calf in preparation for the feast, the rock, the tree of Mamre, and the house (tent)
Very few artists before Rublev dared to eliminate all the narrative elements from the story, leaving only the three angels; usually those who did so had to deal with limited space. The results of their efforts did not find general acceptance or many copyists. Rublev was the first to make a conscious decision not to include in his composition the figures of Abraham and Sarah because he did not set out to illustrate the story of the hospitality of Abraham, as did many painters before him, but to convey through his image the idea of the unity and indivisibility of the three persons of the Trinity.
The doctrine of the Trinity, difficult to explain logically, found various interpretations. Some thought that the Trinity consisted of God the Father, God the Son, and God the Holy Spirit. Others believed that it was just God and two angels. In the 14th and 15th-century Russia, in the period of many heretical movements, the idea of the Trinity was often questioned. The heretics in Novgorod claimed that it is not permissible to paint the Trinity on icons because Abraham did not see the Trinity but only God and two angels. Other heretics rejected the idea of the three hypostases of God altogether. The church fought the heresies with all the means it had -- usually with polemical treaties, but also with force, if necessary. Russian icon painters before Rublev subscribed to the same point of view that Abraham was visited by God (in Christ's image) and two angels. Hence, Christ was represented in icons of the Trinity as the middle angel and was symbolically set apart either by a halo with a cross, by a considerable enlargement of his figure, by widely spread wings or by a scroll in His hand.