Why did guilds want to influence the city government?

Guilds performed a variety of important functions in the local economy. They established a monopoly of trade in their locality or within a particular branch of industry or commerce; they set and maintained standards for the quality of goods and the integrity of trading practices in that industry; they worked to maintain stable prices for their goods and commodities; and they sought to control town or city governments in order to further the interests of the guild members and achieve their economic objectives.

where is the section with the question?