Monastery of Santa María de Nogales, Cistercian monastery ruins in San Esteban de Nogales, Spain.

The Monastery of Santa María de Nogales is a ruined Cistercian convent on the banks of the Ería River near San Esteban de Nogales, built from the second half of the 12th century. Its church was consecrated in 1172, and a new church was completed around 1249. Today the collapsed stonework barely reveals its original layout.

A nobleman and his wife received the Villa de Nogales in 1149, which led to the monastery's establishment. The site grew into an important religious center for the region over the following centuries.

The monastery was linked from its beginnings to the Cistercian monastery of Santa María de Moreruela, which sent a dozen monks to complete its foundation. The church, consecrated in 1172, held three tombs commissioned by Sancha Ponce de Cabrera for her husband Vela Gutiérrez, a deceased son and herself. Noble descendants such as Aldonza Alfonso de León, illegitimate daughter of Alfonso IX, were also buried there.

The site faces decay and requires careful handling during a visit. Watch for uneven ground and loose stones, as structures are unstable in many areas.

The 16th-century marble tombs of Suero de Quiñones and his wife Elvira de Zúñiga, carved in the style of Pompeo Leoni, are now held by the Hispanic Society of America in New York, not at the ruined monastery.