He had become an energetic propagandist of the new Zionism in England by the Third Zionist Congress in 1899, at which he and Jacob de Haas were elected as members of the ZO's Propaganda Committee.
He found four Jewish backers, including Leopold Kessler, a mining engineer who had recently returned from South Africa with considerable substance.
He remained a friend and powerful ally of Dr Moses Gaster, known as the haham, or Chief Rabbi of Sephardic Jews in Britain.
"[5] Israel Zangwill, Head of ITO (International Territorialist Organization), also feared Russian Pogroms and the treatment meted out to the 'vile Jew'.
Greenberg concurred that the British government had a duty to pressurize the Tsarist regime to desist from the murder of civilians.
The lawyer Greenberg chose to draw up the Articles of Association of The Jewish Chronicle was a Liberal Member of Parliament (MP) by the name of David Lloyd George.
Chamberlain later rose to become Secretary for the Colonies in 1902, and Greenberg felt he could approach him with the request that he give the Jewish people a homeland, somewhere in the British Empire, preferably in what is now Israel.
But once Germany violated Belgian neutrality, Greenberg had to abandon Russian Jewry, and claimed that Britain should join Russia in a war against Austria/Germany.
Early in 1915, Greenberg and Zangwill lobbied the Foreign Office vigorously opposing Weizmann's World View of a Zionist homeland.
At this point, Weizmann made an interesting discovery: he found it was possible to extract acetate, needed to produce dynamite, from chestnuts.
Greenberg was present at an important meeting with Sir Mark Sykes on Sunday 28 January 1917, when the government unequivocally backed military action.
Greenberg had long subscribed to the intellectual Zionist Theory that Jews were naturally homeless people, perpetually in search of salvation.
Lucien Wolf and the Conjoint Committee had tried to limit damage to their cause, but a statement in The Times of 24 May 1917 revealed the extent of the split in Jewry about Zionist ambitions.
Lord Walter Rothschild and Zionist leader, Chaim Weizmann quickly issued rebuttals, that did harm to The Jewish Chronicle's claim to be a voice for Anglo-Jewry.
[11] Greenberg remained a moderating influence, but the Great War changed forever relations within British Jewry.
The casket containing his ashes arrived in Haifa in November 1931, but the Orthodox rabbinate in Jerusalem insisted that since Jewish law prohibits cremation, it could not be buried in consecrated ground.
In January 1932, Joe Linton, one of Weizmann's aides, suggested burying the casket in Herbert Bentwich's private garden near Mount Scopus.