Final answer:
The question appears to contain a mix-up regarding St. Denis. In the context of Spanish colonization, Catholic missionaries played a significant role in fostering the spread of Catholicism among the indigenous population, which, in turn, contributed to the growth of the Spanish mission system.
Step-by-step explanation:
The question asks how did St. Denis help the Spanish mission system grow. The growth of the Spanish mission system was not directly influenced by a historical figure named St. Denis in the context of the Spanish missionaries and their work in the New World. The provided materials, however, discuss the larger process of how Catholic missionaries, including groups like the Jesuits and Franciscans, carried out their efforts to convert and educate Native Americans, as well as the Spanish intention of imposing Catholicism as part of their colonial strategy. Missionaries argued against the exploitative encomienda system, and provided a bridge between Spanish colonists and native populations, fostering the spread of Catholicism and thus contributing to the growth of the Spanish mission system.
It appears that there may be a mix-up with the question as it directly mentions St. Denis, who does not seem to be related to the topic at hand. However, focusing on the broader efforts of Catholic missionaries in the Spanish colonies, it is clear that the effort to convert Native Americans and their opposition to the harsh labor systems were significant in the growth of the Spanish mission system. The expulsion of the Jesuits was a turning point that reflected the tensions between secular and religious authorities in colonial administration.