The competition for the cathedral of Saint John the Divine in New York was announced in France in the publication Semaine des constructeurs in July 1888. Bossan therefore designed this project just before his death, as he died at the end of that same month. That was why this drawing was not one of the works received by the competition jury, who in the end chose the design submitted by the firm Heins and Lafarge.
This design is imbued with Bossan's very personal architectural idiom. The central part of the elevation is similar to the facade of Notre-Dame de Fourvière in Lyon (1872-1884), his most famous building. The cupola and drum recall those found above the crossing of the transept and nave in the church at La Louvesc (Ardèche) and the church at Ars (now Ars-sur-Formans in the department of the Ain). The ornamental details (palms, crosses, arcatures) reveal the influence of his master Henri Labrouste. Bossan brings in references to classical Greece and to the Middle Ages, associations that are characteristic of his decorative vocabulary.
The development of these large-scale constructions contrasted sharply with the architect's other works, and was certainly a result of the specifications laid down: the project administrators wanted to rival the imposing Catholic cathedral of Saint Patrick, built in New York in a Neo-Gothic style a few years earlier. For Bossan, whose Catholic fervour was steeped in mystical spirituality, the challenge was to put forward a design that could bring together the whole of the Christian community, in line with his architectural style in which he sought to reconcile the main principles of classical and medieval architecture. This is probably why he decided to cover the whole building with a vast cupola like that of the Hagia Sophia in Constantinople, giving an undeniable monumentality to his design.