In 1902–03 Herzl was invited to give evidence before the British Royal Commission on Alien Immigration. The appearance brought him into close contact with members of the British government, particularly with Joseph Chamberlain, then secretary of state for the colonies, through whom he negotiated with the Egyptian government for a charter for the settlement of the Jews in Al 'Arish, in the Sinai Peninsula, adjoining southern Palestine.
On the failure of that scheme, which took him to Cairo, he received, through L. J. Greenberg, an offer (Aug., 1903) on the part of the British government to facilitate a large Jewish settlement, with autonomous government and under British suzerainty, in British East Africa. At the same time, the Zionist movement being threatened by the Russian government, he visited St. Petersburg and was received by Sergei Witte, then finance minister, and Viacheslav Plehve, minister of the interior, the latter of whom placed on record the attitude of his government toward the Zionist movement. On that occasion Herzl submitted proposals for the amelioration of the Jewish position in Russia. He published the Russian statement, and brought the British offer, commonly known as the "Uganda Project," before the Sixth Zionist Congress (Basel, August 1903), carrying the majority (295:178, 98 abstentions) with him on the question of investigating this offer, after the Russian delegation stormed out.
In 1905 after investigation the Congress decided to decline the British offer and firmly committed itself to a Jewish home land in the historic Land of Israel.
Herzl did not live to see the rejection of the Uganda plan; he died in Edlach, Lower Austria in 1904 of heart failure at age 44. Herzl's will stipulated that he should have the poorest-class funeral without speeches or flowers and he added, "I wish to be buried in the vault beside my father, and to lie there till the Jewish people shall take my remains to Palestine". In 1949 his remains were moved from Vienna to be reburied on Mount Herzl in Jerusalem.
 Herzl's grandfathers, both of whom he knew, were more closely related to traditional Judaism than his parents, yet two of his paternal grandfather's brothers and his maternal grandmother's brother exemplify complete estrangement and rejection of Judaism on the one hand, and utter loyalty and devotion to Judaism and Erez Israel. Herzl's paternal grandfather Simon Loeb Herzl, reportedly attended the Sephardic Zionist Yehudah Alkalay's synagogue in Semlin, Serbia, and the two frequently visited. (Alkalai studied in Jerusalem under different rabbis and came under the influence of the Kabbalah - Jewish mysticism. In 1825 he became Rabbi of Semlin.) Grandfather Simon Loeb Herzl "had his hands on" one of the first copies of Alkalay's 1857 work prescribing the "return of the Jews to the Holy Land and renewed glory of Jerusalem." Contemporary scholars conclude that Herzl's own implementation of modem Zionism was undoubtedly influenced by that relationship. In the town of Zemun (near Belgrade, Serbia, Yugoslavia) the grave of Theodor Herzl’s grandparents can be visited. 
Jacob Herzl (l835-1902), Theodor's father, was a highly successful businessman. Herzl's mother, Jeanette (nee Diamant) was a handsome and wise woman. She took pride in her son, but did not have a successful relationship with her daughter-in-law.  Herzl had one sister, Pauline, a year older than him, who died suddenly on February 7, 1878 of typhus. The remains of Herzl's parents and sister were re-buried on Mount Herzl in Jerulsalem.
In 1889 he married Julie Naschauer, daughter of a wealthy Jewish businessman in Vienna. The marriage was unhappy, although three children were born to it. Herzl had a strong attachment to his mother, who was unable to get along with his wife. These difficulties were increased by the political activities of his later years, in which his wife took little interest.
All three children died tragically.
Pauline suffered from mental illness and drug addiction. She died in 1930 at the age of 40, apparently of a morphine overdose. Hans, a converted Catholic, committed suicide (gunshot) the day of sister Pauline's funeral. He was 39. In 2006 the remains of two of his children were moved from Bordeaux, France, and placed alongside their father. 
The youngest daughter, Trude Margarethe , (officially Margarethe, 1893-1943) married Richard Neumann. He lost his fortune in the economic depression. He was burdened by the steep costs of hospitalizing Trude, who was mentally ill, and was finding it difficult to raise the money required to send his son Stephan, 14, to a boarding school in London. After spending many years in hospitals, Trude was taken by the Nazis to Theresienstadt where she died.
Trude's son (Herzl's only grandchild), Stephan Theodor Neumann (1918-1946) grew up in England and changed his surname from Neumann to Norman. During WWII, Stephan became a captain in the British army and visited Palestine in 1945 and 1946. After leaving the army he became an economic adviser in the British mission in Washington, D.C., where he committed suicide by jumging from a bridge into a river.
Judenstaat and Altneuland
Whereas his first brochure and his first congress address lacked all religious thought, and his famous remark that the return to Zion would be preceded by a return to Judaism seemed at the moment due rather to a sudden inspiration than to deep thought, subsequent events have proved that he was right. His last literary work, Altneuland (in Eng. The Old New Land), is devoted to Zionism. The author occupied his free time for three years in writing what he believed might be accomplished by 1923. It is less a novel, though the form is that of romance, than a serious forecasting of what can be done when one generation shall have passed. The keynotes of the story are the love for Zion, the insistence upon the fact that the changes in life suggested are not utopian, but are to be brought about simply by grouping all the best efforts and ideals of every race and nation; and each such effort is quoted and referred to in such a manner as to show that Altneuland ("Old-New land"), though blossoming through the skill of the Jew, will in reality be the product of the benevolent efforts of all the members of the human family.
Herzl envisioned a Jewish state which combined both a modern Jewish culture with the best of the European heritage. Thus a Palace of Peace would be built in Jerusalem, arbitrating international disputes - but at the same time the Temple would be rebuilt, but on modern principles. He did not envision the Jewish inhabitants of the state being religious, but there is much respect for religion in the public sphere. Many languages are spoken - Hebrew is not the main tongue. Proponents of a Jewish cultural rebirth, such as Ahad Ha'am were critical of Altneuland.
Herzl did not foresee any conflict between Jews and Arabs. The one Arab character in Altneuland, Reshid Bey, who is one of the leaders of the "New Society", is very grateful to his Jewish neighbors for improving the economic condition of Palestine and sees no cause for conflict. All non-Jews have equal rights, and an attempt by a fanatical rabbi to disenfranchise the non-Jewish citizens of their rights fails in the election which is the center of the main political plot of the novel.
The name of Tel Aviv is the title given to the Hebrew translation of Altneuland by the translator, Nahum Sokolov. This name, which comes from Ezekiel 3:15, means tell — an ancient mound formed when a town is built on its own debris for thousands of years — of spring. The name was later applied to the new town built outside of Jaffa, which went on to become the second-largest city in Israel. Nearby is Herzlia, named in honor of Herzl.
Books written by Theodor Herzl
- The Jewish State (Der Judenstaat) (ISBN 1-59986-998-5)
- The Old New Land (Altneuland) (ISBN 1-55876-160-8)
Biographies of Theodor Herzl
- Herzl, King of the Jews: A Psychoanalytic Biography of Theodor Herzl by Avner Falk, University Press of America, 1993, ISBN 0-8191-8925-1
"Herzl" by Amos Elon - published 1975 by Holt, Rinehart and Winston. ISBN 0-03-013126-X. Amos Elon has also written "The Israelis: Founders and Sons", and "Jerusalem: City of Mirrors". His biography of Herzl is also a portrait of Europe at the end of the 19th century.
- ^ 'Obituary', The Times, Thursday, July 07, 1904; pg. 10; Issue 37440; col B.
- ^ Herzl's children reburied in Israel. Canadian Jewish News 28 September 2006