What is the main goal pursued by Yuri Dolgoruky?

Yuri Dolgoruky was a prince in Rostov-Suzdal lands. All his life, he helped his brothers to hold the Kiev principality and Pereyaslavl. Prince Dolgoruky attracted migrant families to his lands who became free farmers. Under him, many cities were built – Yuryev, Dmitrov, Kostroma, Dubna and others. Yuri paid much attention to the construction of a fortress – a city – Moscow. The prince built wooden fortifications and surrounded the city under construction with a deep moat. Moscow has become a defense city and a gathering point for squads preparing for a military campaign.