Built in 1259 under the patronage of King D. Afonso III, the church became the largest example of the Gothic mendicant of Santarém, the result of the royal funding of Queen Santa Isabel and D. Dinis, her husband. These supports will have defined him not only the structure and the wide dimensions, but also the development of an important monastic house (disappeared after 1907). In the first half of the 17th century, the church underwent major renovations that altered its shape and volume, namely the suppression of the transept, the division of the large body, a new coffered ceiling and the application of Mannerist tile covering, removed within the scope restoration campaigns in the mid-20th century. The plan of the current Church features three long naves of eight sections composed of tall Gothic columns decorated with fresco paintings and carved capitals, whose heraldry documents the royal patronage. The lighting is done through a rosette and through multiple cracks and windows. Of its tomb heritage, the gothic tomb of D. Leonor Afonso stands out, professes clarissa and bastard daughter of the founding king.