Original sentence: In 1923, while studying at the Vatican, Szekely translated several obscure Aramaic texts which, he claimed, proved that the Essenes were vegetarians, and that vegetarianism was prescribed by Jesus
Edited sentence: In 1923, while studying at the Vatican, Szekely translated several obscure Aramaic texts which, he claimed, proved that the Essenes (according to him early Christians, in reality a jewish sect) were vegetarians, and that vegetarianism was prescribed by Jesus