The Lanz factory in Mannheim, Germany, built steam engines and motor cultivators before producting the famous Lanz Bulldog in 1921. Nearly one-quarter million of these simple tractors were built over the next thirty years. Lanz was purchased by John Deere in 1956. By 1958, the Bulldog was being produced in John Deere green and the Deere name appeared alongside Lanz. By the late 1960s, the Lanz name disappeared completely, although the Mannheim factory is still in operation.
Deere & Company - official site
LBVW - German antique tractor club with an interest in the Lanz Bulldog