And he has more to say:
dpal ldan rgyal po De gzhon nu| dus su lo ni bco brgyad la| 'Phags pa lha yis byas pa 'i[|] Dpal ldan gnas ni shar phyogs su| dge slong rnams kyi gtsug lag khang gi phyogs gzhan gyis gsal bar btab pas| Rdo rje sems dpa'i drin gyis bdag gis rgyud 'grel 'di ni rnam par brtsams||
The text is of course quite clearly corrupt. But what he seems to be saying is that during the 18th regnal year of De gzhon nu (perhaps Bde gzhon nu for *Ānandakumāra?) he composed through the grace of Vajrasattva this commentary to the [Guhyasamāja]tantra east of a place called Dpal ldan gnas (*Śrīsthāna or something similar) founded by Āryadeva. The rest is obscure to me. Perhaps what he means that this place was illuminated by the presence of chapels and monks?
Find out more about this king and the place, and we may just have a pretty solid date for the notoriously evasive exegetes of the Guhyasamāja. etat tu yuṣmābhir eva kartavyam.