'Achaian' belongs to the stripe paintings which Riley made between 1980 and 1985. In late 1979 she had visited Egypt for the first time. As a result of this experience Riley's use of colour underwent a further major development and she evolved what she called her 'Egyptian palette'. This is characterised by colours of greater intensity than she had used previously, a development accompanied by her decision to change from acrylic to oil paint. At the same time she returned to using stripes as the basis of her compositions. As in her stripe paintings of 1967-73, Riley's use of the stripe format represents a desire to use 'unassertive forms' which allow the colours to establish the painting's structure.