The getRuler2 arguments are appended to the api call as such:
&getRuler2={ruler name}
The possible arguments are:
ADDEDOMAROS
Aedic Sia
AESV
AGR
ALE SCA
Amminus
ANDOCO
ANTED (Dobunni)
ANTED (Iceni)
ANTEDIO SIA
AVN CO
BODVOC
CAM CVN AGR
CAN DVRO
CARA[TACUS]
Cat
CATTI
Commios
COMVX
CORIO
CRAB
Cunobelin
DIAS
DIRAS
Dubnovellaunos
DVMNOCO TIGIR SENO
ECE
ECEN
Ecen/Ece
ED(N)
Edn/Ed
EISV
Epaticcus
Eppillus
Gallo-Belgic
IATISON
IISVPRASV
INAM
Inam’/'Inara
Uninscribed
Potin
RVES
SAENV
SAM
SEGO
SVB ESVPRASTO ESICO FECIT
Tasciovanus
Tincomarus
Vep
VEP CORF
VEPO CORF
Verica
VOLISIOS CARTIVEL
VOLISIOS DUMNOCOVEROS
VOLISIOS DUMNOVELLAUNOS
Vosenos
Same caveat as getRuler1 use a %20 for spaces in strings. This field is rarely used.