The career of the French saint Vincent de Paul has attracted the attention of hundreds of authors since his death in 1660, but the fate of his legacy - entrusted to the body of priests called the Congregation of the Mission (Lazarists) - remains vastly neglected. De Paul spent a lifetime working for the reform of the clergy and the evangelization of the rural poor. After his death, his ethos was universally lauded as one of the most important elements in the regeneration of the French church, but what happened to this ethos after he died? This book provides a thorough examination of the major activities of de Paul's immediate followers. It begins by analysing the unique model of religious life designed by de Paul - a model created in contradistinction to more worldly clerical institutes, above all the Society of Jesus. Before he died, de Paul made very clear that fidelity to this model demanded that his disciples avoid the corridors of power. However, this book follows the subsequent departures from this command to demonstrate that the Congregation became one of the most powerful orders in France. The book includes a study of the termination of the little-known Madagascar mission, which was closed in 1671. This mission, replete with colonial scandal and mismanagement, revealed the terrible pressures on de Paul's followers in the decade after his demise. The end of the mission occasioned the first major reassessment of the Congregation's goals as a missionary institute, and involved abandoning some of the goals the founder had nourished. The rest of the book reveals how the Lazarists recovered from the setbacks of Madagascar, famously becoming parish priests of Louis XIV at Versailles in 1672. From then on, fealty to Louis XIV gradually trumped fidelity to de Paul. The book also investigates the darker side of the Congregation's novel alliance with the monarch, by examining its treatment of Huguenot prisoners at Marseille later in the century, and its involvement with the slave trade in the Indian Ocean. This study is a wide-ranging investigation of the Lazarists' activities in the French Empire, ultimately concluding that they eclipsed the Society of Jesus. Finally, it contributes new information to the literature on Louis XIV's prickly relationship with religious agents that will surprise historians working in this area.