即位
Common
Noun
Irregular
Intransitive
1
noun (common) (futsuumeishi)noun or participle which takes the aux. verb suruintransitive verb
accession to the throne;enthronement
エリザベス女王の即位５０年の記念に贈られたものみたいです。
It seems it was a gift for the 50th anniversary of Queen Elizabeth's accession to the throne.