This is a reference to Napoleon III (1808-1873), the Emperor of the French, who was regarded by many historians as the most outstanding monarch of his day in the West.
Bahá’u’lláh addressed two Tablets to Napoleon III, in the second of which He clearly prophesied that Napoleon’s kingdom would be "thrown into confusion", that his "empire shall pass" from his hands, and that his people would experience great "commotions".
Within a year, Napoleon III suffered a resounding defeat, at the hands of Kaiser William I, at the Battle of Sedan in 1870. He went in exile to England, where he died three years later.
119. O people of Constantinople! [#89]
The word here translated as "Constantinople" is, in the original, "Ar-Rúm" or "Rome". This term has generally been used in the Middle East to designate Constantinople and the Eastern Roman Empire, then the city of Byzantium and its empire, and later the Ottoman Empire.
120. O Spot that art situate on the shores of the two seas! [#89]
This is a reference to Constantinople, now called Istanbul. Located on the Bosphorus, a strait about 31 kilometres long which links the Black Sea and the Sea of Marmara, it is the largest city and seaport of Turkey.
Constantinople was the capital of the Ottoman Empire from 1453 until 1922. During Bahá’u’lláh’s sojourn in this city, the tyrannical Sultan ‘Abdu’l-‘Azíz occupied the throne. The Ottoman Sultans were also the Caliphs, the leaders of Sunní Islám. Bahá’u’lláh anticipated the fall of the Caliphate, which was abolished in 1924.