BOROUGH. At no time before 1835 can a precise legal definition be found for the borough. Alike in the 11th and in the 18th century the popular use of the word covers so wide a variation in custom and so long a gradation of powers that both lawyer and historian are defeated in the attempt to frame an ade quate generalization. The borough, nevertheless, plays a most important part in the history of English self-government. A natural economic centre which acquired mercantile and adminis trative independence, it became the field where the political in stincts of the middle-class first found scope and thus training ground for a wider citizenship. The Plantagenet device of sum moning representatives of the boroughs to parliaments trans ferred to the national stage men who were well used to responsi bility. The life of numbers of vigorous independent political entities went to build up the House of Commons : it was the communitas communitatum, the assembly of the communities.