Born in St. Petersburg in 1834, Julian Boncza Tomaszewski trained at the St. Petersburg Academy of Art with Feodor Antonov Bruni and was first mentioned in 1856 for medals received for paintings based on the New Testament. In 1860 he left for Italy to complete his training and from 1861 until 1877 he lived in Paris, participating at the yearly Salons.

Boncza Tomaszewski considered himself Polish and adopted early on a Latin signature. Nevertheless, he was patronized by the Russian Imperial family, and his painting 'The Three Rulers of Russia' was acquired by the Emperor Alexander III and was part of the Imperial collection in the Winter Palace.