Jacob Halder (active 1576-1608) was Master Workman at the Almain Armoury at Greenwich from 1576 until his death in 1608. In this capacity he was responsible for two of the most important armours in the Royal Collection – those made for Sir Christopher Hatton (RCIN 72835) and for Henry, Prince of Wales (RCIN 72831).

Halder, who was born and trained in Landshut, Bavaria, is first recorded at Greenwich in a list of Almains (German armourers) of about 1557. He succeeded John Kelte as Master Workman in 1576, and from this time brought a strong German influence to the decoration of armours.  During his tenure as Master Workman, Halder also produced a full-colour album illustrating and labelling all the decorated armours made at Greenwich.  Among these were armours for Elizabeth I's leading courtiers, advisors and military leaders, including that for 'Sur Cristofer Hattone'.

The royal workshops at Greenwich were established by Henry VIII between 1511 and 1515 and were the main suppliers of armour to the monarch and court from this time until the Civil War. Their armours are distinguished by their high standard of construction and their often elaborate decoration incorporating etching, gilding and colour.  The armours frequently included interchangeable pieces so that the wearer could configure them for different activities in the field (in combat) and at the tournament.