Conversation so far:
What was A. C. Bhaktivedanta Swami Prabhupada's religion?
A. C. Bhaktivedanta Swami Prabhupada was Hindu.
What was A. C. Bhaktivedanta Swami Prabhupada's training like?
In 1922, when A. C. Bhaktivedanta Swami Prabhupada first met his spiritual master, Bhaktisiddhanta Sarasvati Thakura, he was requested to spread the message of Chaitanya Mahaprabhu in the English language.
Did A. C. Bhaktivedanta Swami Prabhupada spread the message of Chaitanya Mahaprabhu in the English language?
In 1944, A. C. Bhaktivedanta Swami Prabhupada started the publication called Back to Godhead.

Question: how long did the publication last?
Self-contained rewrite: How long did the publicaiton Back to Godhead last?