CHRISTIAN F HEISE SILVER STRAINER 1929. The maker of this piece of Danish silver is Christian F Heise who worked from 1904 to 1932. Beneath the handle are his initials and the Three Tower mark of Danish silver & 29. The three Tower mark of Copenhage became the Danish standsard silver mark for all cities in 1893. It guarantees a purity of 826/1000. Each year has a slightly different design of the three towers.