The exchange of rings is aformal sign that themarriage contract, or pact,has been sealed. The ringfinger of the left hand waschosen because ancientcultures believed a veinconnected that fingerdirectly to the heart.
The exchange of a ringor rings is a part of themarriage ceremony;the current practice isknown as a "double-ring" ceremony, withboth the bride andgroom receiving a ring.
In a religious ceremony, the officiant blessesthe rings. During the ceremony, the groommay choose to place only the wedding ring onthe bride's finger or both the wedding andengagement ring, in the correct order, ofcourse.
The bride may choose towear her engagementring on her right handduring the ceremonyand move it to her lefthand afterward, or thegroom can place bothrings on her fingerduring the ceremony.
The rings traditionally are kept by the groom, the best man, the maid (or matron) of honor or the ring bearer prior to their use in the ceremony.
Source: http://www.ehow.com/way_5339375_wedding-engagement-ring-
go-first.html
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