Latin form ultimately preferred to avoid distancing from Caesar de Grassis.
Cath. Ch. Rota Romana. Decisionum Sacrae Rotae Romanae per RR. PP. DD. Achillem et Caesarem de Grassis ... libri duo, 1601 t.p., etc. (Achilles de Grassis)
Catholic Church. Apostolic Nunciature (Germany). Nuntiaturen des Pietro Camaiani und Achille de Grassi ... 1959 p. xii (b. 1498) p. xiii (d. 8/8/1558)
Cerchiari, E. Capellani papae, v. 2, 1920 no. 402, p. 98 (Achilles de Grassis; auditor of the Rota 1547-1551)
New Cath. encyc. (Grassi (de Grassis), Achille, Bishop of Montefrascona; nephew of Cardinal Achilles de Grassi, the Elder; secretary of the Council of Trent; b. 1498; d. 1555)