The doors of Llandaff Cathedral have been locked as a new bishop is elected.
An electoral college of 47 people, including all the bishops in Wales, are meeting to vote on a confidential candidates list.
The election - which could take up to three days - follows the retirement of Dr Barry Morgan at the end of January.
The new bishop will be the 72nd Bishop of Llandaff, a diocese which serves nearly half the population of Wales.
The electoral college is made up of representatives from all six Welsh dioceses.
Once a bishop is elected, he or she will have up to 28 days to accept the position and the election will be formally confirmed in April.