[a] His published writings are a key source for the history and ethnography of the Nahuas of central Mexico in the immediate post-conquest period as well as for the challenges of Christian evangelization.
[1] He also chose Catalina de Bustamante to teach in the first school for indigenous girls in the New World and was aligned with the educational aspect of Franciscan missionary efforts.
He suggested for the native leaders to complain to Bishop Juan de Zumárraga about Guzmán, but the latter accused him of trying to instigate a revolt among the Indians against the Spanish.
Motolinía believed that God would protect the Indians once converted and that the missionary work thus was more important than fighting the encomienda system, and defended it along with evangelization.
In fact, in a famous letter to King Charles V of Spain, he undertook a virulent attack on Las Casas, intending to discredit him completely.
In the time of the conquest Mexico's devastating plagues had reduced the indigenous population considerably and the Franciscans feared for the souls of Indians who died without baptism.
The Dominican Order was famous for its adherence to firm doctrinal positions, which meant that they refused baptism to Indians in Mexico if they were deemed to lack knowledge in the tenets of Christianity.
By 1555, Motolinia expressed hope to King Charles V that both secular and religious power in the Americas would be consolidated under the Spanish Crown as a theocracy, following the book of the Apocalypse.
[7] The children had been put in the care of lords of Tlaxcala by the leader of the Twelve Apostles of Mexico, Martín de Valencia, who Motolinia thought would be especially saddened by the murders.
However, as one of the earliest friars evangelizing in the densest area of Nahua populations, what he wrote is extremely important as a record of indigenous life and first encounters with the Spaniards.
An English translation of significant portions of Motolinia's works was done by Elizabeth Andros Foster in 1950 for the Cortés Society and reissued in 1973 by Greenwood Press.