There is no record of how many of them there were, but it is generally thought that there were only three because of the three gifts mentioned. The early church saw each of the gifts as representing different aspects of Jesus' life:
Gold - a valuable metal suitable for a king, reminding us that Jesus is King of Kings.
Frankincense - a sweet smelling incense used in the temple to worship God reminding us that Jesus is God.
Myrrh - a fragrant spice put on dead bodies before they were buried, reminding us that Jesus was to die so that He could be our Saviour.

Epiphany is about more than the wise men, though, and we have a cycle of ‘Sundays of the Epiphany’ ending with the Presentation of Christ in the Temple or Candlemas on February 2nd. During this cycle other ways are remembered in which Christ was manifested. The first Sunday following the Epiphany is always the ‘Baptism of Christ.’ Jesus was baptised by John the Baptist in the river Jordan and a voice was heard proclaiming him to be God’s Son. This was a profound moment of revelation of the identity of Christ. The colour for the season of Epiphany is white.

The season of Epiphany extends from January 6th until February 2nd, Candlemas, the Presentation of Christ in the Temple.

The period between December 25th and January 6th is known as the Twelve Days of Christmas (the last six days of the old year - 26, 27, 28, 29, 30, 31 December - and the first six days of the New Year - 1, 2, 3, 4, 5, 6 January). Twelfth night is the evening of January 5th. Twelfth day is January 6th, the last day of Christmas and the feast of Epiphany.