catholicize

catholicise

verb

to make or become catholic
(often capital) to convert to or become converted to Catholicism

Derived Formscatholicization or catholicisation, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012