This charming drawing was produced by Sandro Botticelli circa 1475-1480. It is one of a number of drawings which have not been confidently attributed to any fresco. Although angels were common in his work, none link directly to this particular sketch. Where a link can be made, drawings become far easier to date, hence the wide approximation of this piece.
Frescos by Botticelli which also featured angels include Madonna with Lillies and Eight Angels, Madonna and Child and Two Angels, Virgin and Child with an Angel, Madonna and Child with Two Angels, The Virgin and Child Surrounded by Five Angels and Virgin and Child with Two Angels. This symbolic and aesthetically stunning religious character lavishes thousands of paintings from the Renaissance era.
The curved nature of this artwork is normally used as a study piece for completing a fresco which laps around curved architectural interiors. During this era there were many commissions for decorating cathedrals and other religious buildings. Artists would then need to adapt to awkward angles that some buildings would serve up. In the modern day, of course, artists tend to use rectanglar canvases which is far easier to work with.
Interesting comparisons can be made by the way different artists captured angels in different ways. Compare, for example, this Three Angels drawing with Tobias and the Angel by Leonardo da Vinci, The Virgin with Angels by William Bouguereau and Fall of the Rebel Angels by Pieter Bruegel.