Special items of the hierarchical service are the dikerion and the trikerion. These are two hand-held, ornamental candlesticks in which two (dikerion) or three (trikerion) candles are placed. The use of the dikerion and trikerion at the patriarchal liturgy began in the twelfth century.  Originally these candlesticks were ascribed only to kings and patriarchs (and not to all bishops) as they were perceived as attributes reflecting the dignity of teaching. This is mentioned in the twelfth century by Theodore Balsamon, the patriarch of Antioch, who insisted that the right to bless the faithful with candlesticks belonged to kings, patriarchs, autocephalous archbishops of Bulgaria and Cyprus, and also a few metropolitans to whom the kings had given this right.  You see a similar broadening of use to lower ranks with the mitre and the use of a mitre with a cross atop it.
Later the dikerion and trikerion came to be used by all hierarchs at church services. The trikerion is interpreted symbolically as an indication of the three Persons of the Holy Trinity, while dikerion indicates the two natures of Jesus Christ.  Candles placed in the trikerion and dikerion may be connected at the top in such a way that a single flame is formed. A more common style has crossing candles whose top ends are directed in different directions. 
 Jacob, “Le chandelier a trois branches de l’eveque Pantoleon: A propos de l’inscription de Geroges de Gallipoli,” Bolletino della Badia greca di Grottaferata 53 (1999), 187-199.
Theodore Balsamon Reflections, PG 138, 1016D-11017C.
Simeon of Thessalonica Concerning the Holy Temple 59, 61. PG 155, 721BC.
 Deacon Mikhail Zheltov, “Dikirion” in Orthodox Encyclopedia, vol. 14, 693.
"The bishop is reciting commemorations at the "Transfer of the Gifts or Great Entrance". He would be singing: "May the Lord God remember in His Kingdom [N.N.] always, now and ever, and unto the ages of ages." He is holding the chalice covered with a small veil. There are priests holding blessing crosses to the north and south of the holy doors and the trikirion and dikirion held by subdeacons, as well as subdeacons holding ripdia [fans] over the diskos. We see in the foregound two subdeacons. The one on the north is the candle bearer and the one on the south is the staff bearer [crozier]. The staff is not visible from our perspective but he should have it in this procession. Notice the icon on the analogion of the Baptism of Christ. The apodosis [leave taking] of the Feast of the Baptism is today."
"The bishop is blessing with the trikirion [a triple branched canle symbol of the three persons of the most Holy Trinity] and the dikirion [a double branched candle symbol of the two natures in the one person of Christ] following the deposition of the unconsecrated holy gifts upon the holy table. The bishop says nothing at this blessing but the choir/assembly responds: "Eis polla eti, despota". [Many years, master.] He is wearing the small omophorion which originally was a folded great omophorion [pallium]."
"At the Trisagion when the clergy sing the second "Holy God, Holy Mighty, Holy Immortal, have mercy on us." the bishop makes the sign of the cross with the dikirion [a double branched candle symbol of the two natures in the one person of Christ] over the gospel book."