María wrote "La Cruz del Morro" ("The Cross of El Morro") in 1862, making her the first Puerto Rican to write a dramatic play. The play premiered at Teatro Municipal, San Juan on June 16, 1897 to commemorate the centennial of the English attack on the city. "La Cruz" was based on the attack of the city of San Juan by the Dutch with the intention of invading Puerto Rico in 1625 and the defense by the islanders. In the play, Balduino, the captain of the Dutch navy falls in love with Lola and pursues her. Lola is the wife of Captain Amezquita, a Spanish soldier who is in charge of the defense of el Morro. Balduino promises that the Puerto Rican and Spanish prisoners will be released in exchange for favors from Lola, but she refuses. A final duel between Amezquita and Balduino repairs all greivances. It was not considered a very well-written play, but its patriotic themes inspired loyalty to the Spanish government. The positive representation of female characters in the play makes Maria one of the first feminists of Puerto Rico. The play was recently presented by el Conservatorio de Arte Dramático del Ateneo in March 2011 at the Ateneo Puertorriqueño as part of the XXXIV Festival de Teatro del Ateneo. The production starred Joealis Filippetti, Ricardo Magriñá, Teresita Marrero, Rolando Reyes y Jesús Aguad and was directed by Benigna Ojeda.