Dominique Jean Larrey developed an ambulance volante (flying ambulance) corps, in the service of first the French Republic and then Napoleon Bonaparte, after witnessing the speed with which French horse artillery maneuvered across the battlefield. He also pioneered many modern techniques of army surgery, and field hospitals. His success at not only saving lives but returning soldiers to active duty would be unmatched until the 20th century. From an earlier answer by yours truly:
Consider the 1200 or so Guard casualties at Aspern Essling (from Bowden & Talbot, Armies on the Danube 1809):
Returned to Active Duty 600
Returned to France 354 (including amputees)
Let's think on these numbers for a minute. Two 12-pounder batteries, 12 guns total, firing canister at 100 yards say twice a minute, for an hour, fired a total of roughly 1,440 canister rounds in that time. All that shot inflicted less than one casualty per canister round fired, and barely 0.1 death per canister round fired. That's how good French skirmishers (granted, the Old Guard) were at avoiding fire! After an hour of this, the Austrian artillery retired due to excessive casualties, allowing the successful retreat of French forces back to Lobau Island.
I have seen it claimed that you had to be an Austrian Archduke in order to receive better medical care from the Austrian army than was routinely dispensed to the lowliest private in Le Grande Armee.