Right as an aspen lefe she gan to quake.

Geoffrey Chaucer (1328-1400): Troilus and Creseide. Book ii. Line 1201.

O woman! in our hours of ease

Uncertain, coy, and hard to please,

And variable as the shade

By the light quivering aspen made;

When pain and anguish wring the brow,

A ministering angel thou!

Sir Walter Scott (1771-1832): Marmion. Canto vi. Stanza 30.