Archbishop Anthony Mancini (Andrew Vaughan/Canadian Press)

The Archbishop of the Roman Catholic diocese of Halifax says he's "shocked" by Monday's resignation announcement from Pope Benedict XVI.

Anthony Mancini said he had not heard the news until a colleague in the diocese office asked him at 7:15 a.m. if he'd heard the news.

"I had no idea this was coming. You're a little bit stunned because this is so unusual, unexpected and unheard of", Mancini told Maritime Noon host Norma Lee MacLeod.

A pope has not resigned in nearly 600 years.

The resignation will take effect on Feb. 28. The head of the world's 1.2 billion Catholics cites his deteriorating strength for the resignation.

"I saw him in October and spoke with him personally and my impression of him was that he had lost weight, his face looked drawn and he was extremely tired," said Mancini.

When it comes to Benedict's legacy, Mancini said he'll be remembered for how he handled the church's sex abuse scandals.

"He will have been the one who introduced the most radical changes in terms of how to handle it. While he may be viewed by some as not having done enough... I think he has demonstrated, personally, his wish for a reform of the church so that this behaviour at least will come under greater control than in the past," said Mancini.

"I think he will be appreciated for the steps that he took in this very controversial area."

There will be a gap before his successor is chosen, but it's not yet clear how much time will pass.