The Collaborative International Dictionary of English v.0.48:

Enthronization \En*thron`i*za"tion\, n.
   The act of enthroning; hence, the admission of a bishop to
   his stall or throne in his cathedral.
   [1913 Webster]

WordNet (r) 3.0 (2006):

enthronization
    n 1: the ceremony of installing a new monarch [syn:
         coronation, enthronement, enthronization,
         enthronisation, investiture]