A native of the Netherlands, settled in London, where he soon won a reputation as a skilled and refined engraver. Thanks to the backing of Henry VIII, also went into business as a mathematical-instrument maker. In c. 1544, even Humphrey Cole (c. 1530-1591) worked with Gemini, who probably had contacts with the instrument-makers of Louvain and Antwerp such as Mercator (1512-1594) and Arsenius (? - c. 1580).