Bishops held considerable secular responsibilities. As tenants-in-chief of the crown, they were responsible for providing a quota of armed knights for the king's army. Although they weren't expected be involved in actual combat, several bishops became active military leaders; an example is Thurstan, Archbishop of York, who mustered the army that defeated the Scots at the Battle of the Standard in 1138. Bishops were also responsible for administering their huge estates and presiding in the courts that dealt with civil disputes within them. They were also required to attend royal councils, and with the development of the Parliament of England in the 13th century, the two archbishops and nineteen bishops were required to take their seats in the House of Lords, along with the abbots and priors of the largest religious houses; collectively, they were known as the Lords Spiritual.