The Romans had cotton, but it (and silk) were imported from Asia and were more or less luxury fabrics. However, they also had locally-produced linen (the class

The Romans had cotton, but it (and silk) were imported from Asia and were more or less luxury fabrics. However, they also had locally-produced linen (the classic Roman tunic was made from linen) and linen is considerably more heat-resistant than cotton. If you have a steam iron handy, take a look and you'll see that the ironing temperature for linen is higher than that for cotton.