This presented the discontented nuns with an opportunity to change prioresses again. One of the Prioresses, Isabella (1501), was William Shakespeare's great-aunt. Each house was under three prioresses who presided in the frater and visited the sick. Occasionally the nunnery's superiors were termed abbesses rather than prioresses. Between 1200 and 1537 the priory had nineteen prioresses. Abbesses and prioresses may also be known as "mother superior". Scotland was relatively poorly supplied with nunneries, but prioresses were figures with considerable authority.