There are 3 books in the Brotherhood of the Rose series. The newest book is The League of Night and Fog which came out in 1987.

1
The Brotherhood of the Rose

Book cover of The Brotherhood of the Rose
"Riveting...Crackling...It really moves."
WASHINGTON POST BOOK WORLD
They were orphans, Chris and Saul--raised in a Philadelphia school for boys, bonded by friendship, and devoted to a mysterious man called Eliot. He visited them and brought them candy. He treated them like sons. He trained them to be assassins. Now he…
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2
The Fraternity of the Stone

The Fraternity of the Stone
A former agent is caught in a web of conspiracy so monstrous, it threatens the existance of institutions as powerful as the Catholic Church

3
The League of Night and Fog

The League of Night and Fog
Two brilliant operatives known as Saul and Drew are drawn together to solve a baffling mystery: Why have ten elderly men from around the world been kidnapped? As the agents investigate they are pulled into a violent cycle of revenge that stretches back to World War II—and is now forcing…