Who are greatest thinkers of history, according to Britannica?
A hagiography is a biographic text about a holy person, and typically the term refers to the vita of a Christian saint in the middle ages. In the modern context the term is polemic in nature, as nowadays famous people are admired but usually not considered holy. Instructional texts, and encyclopedias originated from schoolbooks, long presented historical persons as models for good behaviour, or for the opposite. Those black-white-descriptions did not have much room for differentiation, for a critical approach, or for impartiality. The immaculateness of the person was partially the reason for including her in the canon.
Eventually, some very positive descriptions had more base motives. Dennis de Coetlogon (Universal history, 1740s) seemingly expected a reward when praising for example the religious commitment of Edward Howard in the article ‘Heraldry’, or when Anthony Browne, Viscount of Montagu, in ‘Nobility’ is called ‘that excellent nobleman’. 
A peticular problem in small linguistic communities: It is not always easy to obtain reliable sources for a biography, or a neutral person to write about some else. This seems to be the case with the article ”Cseh, Andreo’ in the 1934 Enciklopedio de Esperanto.
There we read that the Catholic priest Cseh, an Hungarian from Rumania, in 1920 elaborated his famous teaching method for Esperanto, and that later in Sweden started his triumphant apostleship through various countries. His courses had such a success that the newspapers wrote about a renaissance of Esperanto. 
The entry was signed by Julia Isbrücker, who together with her husband Jan supported Cseh’s work. In later years, the adult children of the Isbrückers suspected their mother of having an inappropriate relationship with Cseh…
Writing about oneself or about good friends meets a lot of resistance among Wikipedians, although it is not definitely prohibited. In my duties as a mentor at German Wikipedia, I once had a mentee writing about a professor of law (professors are ‘relevant’ by definition). She asked me whether her text was good, and I said it was fine. A minor thing: She wrote that the person obtained his PhD and became a Dr. iur. As the person is a jurist, and as this is the usual title in Germany for a law PhD, the expression ‘Dr. iur.’ is superfluous and can be dropped. After some days, she replied: ‘I have asked again, and Herr Professor said that he does not want that.’ (The poor girl was obviously the assistant of the professor.)
No doubt that Wikipedia is sufficiently critical about Jimmy Wales; the article about him was created in June 2003. But how did the Encyclopaedia Britannica deal with ‘their’ people’? In the 1950s Britannica had a book series ‘Great Books’, and its prospectus presented a number of small portraits: Platon, Shakespeare, Freud and other great thinkers. I wondered, who were the three men in the center of the picture, in the big portraits. Indeed: the publishers of Encyclopaedia Britannica. 
 Jeff Loveland: An Alternative encyclopedia? Dennis de Coetlogon’s Universal history of arts and sciences (1745). Voltaire Foundation, Oxford 2010, p. 153.
 Enciklopedio de Esperanto, 1933/1934, s.v. ‘Cseh, Andreo’.
 Harvey Einbinder: The Myth of the Britannica. MacGibbon & Kee, London 1964 (reprint 1972), p. 337.