A brilliant theologian, Danneels is an outspoken proponent of curial reform and collegiality.

Widely respected, he is seen as a unifying figure acceptable to both conservatives and progressives within the College of Cardinals.

But he is no stranger to controversy. He said it is preferable for HIV-positive people to abstain from having sexual intercourse; but that if they did have sex without a condom, they would be breaking the commandment "thou shalt not kill."

He has also supported the position of appointing more women to key roles at the Vatican but refrained from saying women should be permitted to become priests.

In 2000, he caused consternation in the Vatican by suggesting that popes should not remain in office until they die; rather, that they should have limited terms because modern medicine extended life longer than before.