The British astrologer Ebenezer Sibly (1751 – c. 1799) is perhaps most noted for the chart he published for the July 4th 1776 Independence Day of the United States of America. In discussing with Chris Brennan on The Astrology Podcast the increasing popularity of Placidus houses in England beginning at the end of the 17th century, I cited a reference to Sibly’s translation of Placidus from page 441 the 1898 book The Elements of Astrology by Luke Dennis Broughton:
Although the above direct quote from Broughton’s text indicates that E. Sibly translated the 1650 book by Placidus from Latin into English, the wikipedia entry on Sibly states that the translation was done by his brother Manoah Sibly (1757 – 1840) who was a linguist. In any case, it seems clear that Ebenezer Sibly had access to, and made use of, the translated works of Placidus in the year 1789. Judging from E. Sibly’s published horoscope charts, he was using Placidus houses in his astrological practice at the end of the 18th century.
The following image of the USA Independence chart is taken from Figure No. 53 following page 1055 of Ebenezer Sibly’s A New and Complete Illustration of the Celestial Science of Astrology, published posthumously in 1826.
Sibly’s chart for “America Independence” is cast for London at around 10 pm on 4 July 1776. In London 19 Aquarius 49 is rising on the Ascendant and 13 Sagittarius 12 is the degree of the Midheaven. Modern computer calculations indicate that the “birth time” for this chart is 9:53:14 pm LMT in London, UK. This would correspond to a time of 4:53:15 pm LMT in Philadelphia, PA.
The evidence that Ebenezer Sibly is using Placidus cusps can be seen in the intermediate houses. Sibly’s 2nd house cusp at 20 Aries 00 corresponds to the modern computer calculation of 19 Aries 54 as the 2nd Placidus cusp. Sibly’s 3rd house cusp at 23 Taurus 00 corresponds to the modern calculation of 22 Taurus 25 as the 3rd Placidus cusp. Sibly’s 12th house cusp at 20 Capricorn 00 corresponds to the modern values of 19 Capricorn 46 as the 12th Placidus cusp. Finally, Sibly’s 11th house cusp at 1 Capricorn 0 corresponds to the modern calculation of 0 Capricorn 40 as the 11th Placidus cusp. In fact, Sibly appears to have rounded his numbers to the nearest degree.
The point of this historical interlude is that the prominent British astrologer Ebenezer Sibly, who died around 1799, was influenced by the writings of Placidus, perhaps through his brother’s translations, and was advocating the use of Placidus houses in the final decades of the 18th century, well before the popularization of Tables of Placidus Houses in England in the 1820s. One could argue that Sibly’s adoption of Placidus houses was one of the forces that prompted the adoption of Placidus as the dominant house system in England in the 19th century.