during the first war
Martin Luther
If you mean Leonardo's painting (because lots of other artists have painted this subject) it was commissioned by the Duke of Milan.
Because they were commissioned and paid to do so.
Artists of the time were paid by Patrons who commissioned art work. There were no salaries.
A lot of "freelance" artists are commissioned by games workshop
The definition of commissioned means money paid to a person or group for a service or piece of work. Artists are often commissioned to make art work for people.
Financially support artists. The Medici family commissioned many works by many notable artists of their era.
medici family
Château Mouton Rothschild.
Artists were commissioned by wealthy patrons to create art. The Florentine merchant commissioned da Vinci to paint a portrait of his wife.
They commissioned works by the artists.