See P. Brestyansky Ilona, A Pest-Budai Ötvösség, Budapest, 1977, p. 207 for a record of a Buda town mark of circa 1765, where the standard 13 is unincorporated as it is on this coffin shield.
The arms are possibly those of Kollonitz of Austria.
Jakab Martinovics trained with Antal Marionovics in Ofen from 20 June 1726 until 5 February 1731. The literature records that he became a master in 1741 and obtained citizenship of Ofen in the same year. According to another source, he may have been a journeyman as early as 1732. He trained three apprentices during his career.