 From the 7th century , the forms of some letters began to change . The equal height of the letters was abandoned , with letters acquiring ascenders and descenders . 
 From the 7th century , the forms of some letters began to change . The equal height of the letters was abandoned , with letters acquiring ascenders and descenders . 
From the 7th century , the forms of some letters began to change . The equal height of da letters was abandoned , with letters acquiring ascenders and descenders .