meaning of a sentence
Does the following sentence mean "1. Anthony Gross received several commissions, and 2. After those commissions he became an official artist in the Middle East, India, and north-west Europe"?

Sentence:
Anthony Gross received several proposals for commissions before becoming an official artist in the Middle East, India, and north-west Europe.

Question

meaning of a sentence
Does the following sentence mean "1. Anthony Gross received several commissions, and  2. After those commissions  he became an official artist in the Middle East, India, and north-west Europe"?

Sentence:
Anthony Gross received several proposals for commissions before becoming an official artist in the Middle East, India, and north-west Europe.

Answer

It does not mean that. It means he was asked to be an official artist but did not accept those proposals until the one he finally accepted.

Answer

That sentence in isolation is not enough to understand its exact meaning.

From Wikipedia:

During WWII Gross accepted the role of an official war artist. In 1941, with a temporary commission of captain, Gross was attached to the 9th Army and painted within the Egyptian, Syrian, Palestinian, Kurdistan, Lebanese, and Mesopotamian theatres of war. In 1943 he transferred to India and Burma to witness the front line battle against the Japanese.

Yes, you are right. He received several proposals for (military) commissions.

A military commission is a commissioned officer's official document of appointment.

After he was officially appointed as Captain he went on to become an official war artist in those locations where he was appointed.