The Military Order of Aviz /Ordem Militar de Avis/ known previously to 1910 as the Royal Military Order of Saint Benedict of Aviz /Real Ordem Militar de São Bento de Avis/, and before 1789 as the Knights of Saint Benedict of Aviz /Ordem de São Bento de Avis or Friars of Santa Maria of Évora/ is one of the four former ancient Portuguese military orders. It gave its name and coat of arms to the House of Aviz that ruled Portugal between 1385 and 1580. The founding king of House of Aviz, John I of Portugal, was an illegitimate son of a previous king, and thus not a member of his father's Portuguese House of Burgundy; however, John was the grand master of the Order of Aviz, and thus was known as "John of Aviz." Founded in 1146, it is the oldest Portuguese honorific order.
Boullanger workshop history https://asiamedals.info/threads/orders-made-by-boullanger-paris.30103/.
Silver, gilt, enamel.