Step 1: Comprehension of the Inquiry:
The query seeks to identify the sovereign whose support facilitated the flourishing of the Guler school of Pahari painting, recognized for its naturalistic depiction and subtle artistry.
Step 2: Elaborate Explanation:
The Guler school is frequently regarded as the origin point of the Kangra style of painting. The evolution from the more robust Basohli style to the more sophisticated and naturalistic Guler style occurred in the early 18th century. This artistic progression is strongly linked to the patronage of Raja Govardhan Chand of Guler (reign circa 1741-1773). While painting was present in Guler prior to his rule, it was during his tenure that the school attained its characteristic finesse, refinement, and poetic quality. Artists, potentially from the lineages of Pandit Seu, Manaku, and Nainsukh, worked in his court, establishing a new style that would form the bedrock of the subsequent Kangra Kalam.
\[\begin{array}{rl} \bullet & \text{Raja Balwant Singh provided patronage to Nainsukh at Jasrota, a separate principality.} \\ \bullet & \text{Raja Prakash Chand, the son and successor of Govardhan Chand, continued his father's patronage.} \\ \end{array}\]
Step 3: Conclusive Determination:
The initial significant period of Guler painting, characterized by a distinct and refined style, commenced under the patronage of Raja Govardhan Chand.