On 12 September 1565 the Master of Sinclair, along with other gentry from Fife, signed at St Andrews a bond to the King and Queen to "take part and pursue all rebels into England".

Folio 118 has a blazon of the arms of Orkney and according to Roland Saint-Clair is the earliest specimen of extant Scottish heraldic art on vellum or paper.

Upon the death of Mary, Queen of Scots on 8 February 1587, King James arranged for his courtiers to appear before him in the morning and Henry, Lord Sinclair arrived in a full suit of armour.

The king was angry at him and asked if he had not heard of the general order, to which Sinclair replied "Yes!, this is the proper mourning for the Queen of Scotland".

On 2 December 1596 Henry, Lord Sinclair, was ordered to free William Bonar of Rossie, whom he had imprisoned in Ravenscraig Castle.