abdicate
to abdicate the throne

accede
to accede to the throne

accession
accession to the throne

ascend
to ascend the throne

heir
the heir to the throne

mount
to mount the throne

pretender
pretender to the throne

pretension
pretension to the throne

re-establish
to re-establish a king on the throne

restore
to restore a king to the throne

revest
the king was revested in his throne

succeed
to succeed to the throne

succession
she is next in succession to the throne

throne
...to the throne / to come to the

to
the heir to the throne

usurp
to usurp the throne

vacant
vacant throne