In order to obtain the right to supervise the construction of buildings, especially public buildings, the person approved by the Builders’ guild as a master-builder must be able to draw up designs and elaborate bills of quantities for his buildings. These skills were characteristic of prominent master-builders, especially those working on government contracts. In the first decades of the nineteenth century, however, most continued to supply materials only on the basis of their own estimates, which were usually very accurate. In the village of Lyubenova Mahala there is still a legend of how in 1832 architecton /master-builder/ Dimitar Sergiuv sat on the veranda of the neighbouring café and commanded the delivery of stones. The overworked villagers occasionally grumbled “enough is enough, master”, but he kept saying “more”. Finally he ordered the desperate overworked people to stop, and they were sure that it was all well beyond what was necessary. Eventually, however, on completion of the church, it turned out that all that was left of all the material was one large stone, which still lies behind the apse. So the villagers called it the “Sergius Stone”. Even then Dimitar Sergiuv titled himself as “architecton”, meaning that in the early 19th century he could already draw plans of church buildings. When the official Ottoman authority asked for permission (ferman) to build, it was granted only if there was a description and a drawing.

When the first master appeared before the commissioner of the building – landlord, church board, municipality, he prepared in advance a miniature design of the building, drawn on wrapping paper, or made as a model from wax or wood. After the approval of the model or plan, a contract was concluded. In the contract, the parties agree on materials, deadlines, terms, remuneration, and a guarantee of quality: “Within two years, if any defect is detected in the making of the school, then the master George undertakes to repair it, free of charge, without charging anything for his work.”

A testimonial for the craftsman were the certificates that were issued for work already completed and which characterized his skills, honesty and quality of execution of orders. ‘Honest, reliable, able to build various buildings without needing to be managed by another person’ or ‘certifies that he can fulfill more expensive orders.

After the Liberation, until about 1900, in the absence of state regulation and trained professionals in the fledgling state, reliance was placed on the established master-builders in their capacity of designers and builders. Leading figures among the northern Bulgarian master-builders were Gencho Kanev, Gencho Novakov, Pencho Kolev, Georgi Kolev, Sabcho Sabkov and others from the region of Tryavna.

In 1897, a law forbade design work to be carried out by specialists without a higher architectural or engineering education. The master-builders from Tryavna executed projects developed by qualified specialists. There were many cases in which foremen with highly developed practical skills objected to the execution of engineering and architectural projects. Also, a number of master-builders continued to build their own projects, paying local architects, engineers and technicians to authorize them. The old, decorated architect-practitioner masters retained their status. The skilled master-builders from the Bulgarian lands which remained outside the Principality, continued their design practices unhindered even into the 1920s.