The Royal Society discussed Leeuwenhoek's diploma

March 1, 1680

According to Birch's The History of the Royal Society of London, (vol. IV p. 13), at the February 19 / March 1, 1680 (O.S./N.S.) meeting:

Upon mention of Mr. Leeuwenhoeck's diploma, it was ordered, that the arms of the society be engraved on the silver box to be provided for the diploma.

The image on the right (click to enlarge) shows a detail from Verkolje's portrait of Leeuwenhoek. The silver box is clearly visible, but the Society's seal is not.