Usher

DEF: 1. Cause or mark the start of something new. 2. To show someone where they should go. 3. Person who guides spectators to their seats in a theater.

EX: 1. World War II ushered in the age of nuclear weapons 2. The usher seated them in the front row.

Merriam-Webster Online Dictionary
usher (noun)
1.
a) an officer or servant who has the care of the door of a court, hall, or chamber
b) an officer who walks before a person of rank
c) one who escorts persons to their seats (as in a theater)
2.
archaic an assistant teacher
usher (verb)
transitive verb
1.
to conduct to a place
2.
to precede as an usher, forerunner, or harbinger
3.
intransitive verb
to cause to enter - introduce a new theory ushered into the world to serve as an usher - usher at a wedding