 The name Ladas , derived from that of Alexander the Great 's messenger , had previously been used by Lord Rosebery 's father for a horse who ran unplaced in the 1869 Derby . Rosebery , then an under @-@ graduate at Oxford University , had tipped the horse to his friends as a likely winner and was reportedly mortified by the result . By way of an apology , Rosebery told his friends that if he ever had a horse with a " prime chance " of winning the Derby , he would name him " Ladas " so that they could all " take the tip and back him . " It was the memory of this incident which reportedly persuaded Rosebery to abandon his original plan to name the colt " Hampton Wick " . 
