 The high concentration and more sedentary nature of shepherding in the UK allowed sheep especially adapted to their particular purpose and region to be raised , thereby giving rise to an exceptional variety of breeds in relation to the land mass of the country . This greater variety of breeds also produced a valuable variety of products to compete with the superfine wool of Spanish sheep . By the time of Elizabeth I 's rule , sheep and wool trade was the primary source of tax revenue to the Crown of England and the country was a major influence in the development and spread of sheep husbandry . 
