Millburn, who was bought in 1841, was one of Prince Albert's favourite chargers. He was ridden by Nicholas I, Emperor of Russia, at the review in Windsor Great Park on 5 June 1844. Mercury was presented to Prince Albert by Frederick William IV, King of Prussia, in July 1841, and died in 1852. Following his arrival in England and marriage to Queen Victoria in 1840, Albert was keen to establish a stud at Windsor, where new stables and a Riding School were built in the early 1840s (see RCIN 919770 for a watercolour view of the new Royal Mews painted in 1844). 

Prince Albert's Head Groom was John Kräusslach or Kreuzlach (1820-76), who was in the service of Albert's father Ernest I, Duke of Saxe-Coburg and Gotha and came to England with the Prince in 1840. He was often in attendence during Victoria and Albert's carriage drives and Queen Victoria recorded his death on 7 February 1876 in her journal, writing 'Good faithful old Kräuslach has died, which I am very grieved at. He was the last of dearest Albert's servants, who came over with him just 36 years ago!'

Little is known about Sperling, whose first name was possibly Julius. He exhibited at the Royal Academy in 1845 and 1848, including a picture of a stallion belonging to the King of Württemburg. A lithograph, dated 1848, of a portrait of Baron von Hügel bears the same (draughtman's) signature as visible on RCIN 926155 (see the impression in the National Portrait Gallery).