Sinmun's reign may be characterized by his attempts to consolidate royal authority following unification and to reorganize and systematize the governing apparatus of the newly enlarged Silla state.

[2] It was in late summer 681, not long after coming to power (during the official period of mourning for the recently deceased King Munmu), that a serious revolt broke out against royal authority.

Other scholars see in it a more serious challenge on the part of military leaders (some of whom were also implicated), who following the successful conclusion of the wars of unification saw their own influence and status erode.

In place of the nogeup Sinmun instituted a system wherein officials were allotted only "office land" (jikjeon 職田) from which they were allowed to procure only taxes on grain.

It was following the attempted revolt of Kim Hŭm-dol that Sinmun rescinded the fiefdom granted earlier to Anseung, the would-be king of Goguryeo, and had him come live in the Silla capital of Gyeongju in 683.

Sinmun died in 692, having weathered several serious challenges to royal authority and set the framework for the organization and governance of the expanded Silla state.