Thank you for your contributions.
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I found Marcu Beza's paper: Noui urme romanesti la manastirea Sinai si la Ierusalim. In: Boabe de grau, An V, 1935, nr. 9, p. 552-565.
http://restitutio.bcub.ro/handle/123456789/763
Problem is, nobody knows how the sabre ended up at the Holy Tomb monastery treasury. Beza, working with the assumption that it trully is Brāncoveanu's sabre, postulates that it may have been a gift given to the patriarch, on one of his many visits to the Wallachian prince. The handle is made of ivory, according to him.