Paper on this subject: https://www.google.com/url?q=https://www.academia.edu/4915784/Usted_Ustaad_Etymology_Re_examined&sa=U&ved=2ahUKEwiRlLu07duEAxWoEzQIHfqlA

Paper on this subject: https://www.google.com/url?q=https://www.academia.edu/4915784/Usted_Ustaad_Etymology_Re_examined&sa=U&ved=2ahUKEwiRlLu07duEAxWoEzQIHfqlArwQFnoECAEQAg&usg=AOvVaw0MPkpKfcchI80W4C5Y7nSg https://www.google.com/url?q=https://www.academia.edu/491578... Evidence for "vuestra merced": http://elies.rediris.es/elies22/cap7.htm http://elies.rediris.es/elies22/cap7.htm Much more in-depth treatment of "vuestra merced" etymology: www.academia.edu/39806097/_Fue_vulgar_y_plebeyo_el_origen_de_usted_La_diacron%25C3%25ADa_del_pronombre_de_respeto_desde_la_interfaz_oral_escrito&sa=U&ved=2ahUKEwjc_-qd9tuEAxXFOjQIHWgZDMsQFnoECAYQAg&usg=AOvVaw1A_5QRn5k5EbDqDOzJ-DUy Spanish Corpus: https://www.corpusdelespanol.org/hist-gen/ https://www.corpusdelespanol.org/hist-gen/ Interesting review of dialects of Judeo-Spanish from 1894 where "su merced", "su osted", and "usted" all appear: https://www.cervantesvirtual.com/obra-visor/la-lengua-y-la-literatura--0/html/fef491d8-82b1-11df-acc7-002185ce6064_53.html/marca/osted#2029 https://www.cervantesvirtual.com/obra-visor/la-lengua-y-la-l...