As seen on Downton Abbey season one women rode sidesaddle and had long dressy riding habits. The top hat was also in fashion at this time but a woman would only have worn one while riding - it was usually for men.
This outfit was made for Dame Maggie Smith as Violet Crawley, Dowager Countess of Grantham in Downton Abbey. The fabric was created by reproducing an Edwardian print onto silk. The design was based on a jacket from the era.