Grantham’s family originated as wool merchants in Lincoln, regularly holding municipal office from 1425, and first represented the city in the Reformation Parliament.
Knighted by James I as the new king passed through Lincolnshire on his way to London in 1603, Grantham was returned for Lincoln to the first Jacobean Parliament. In the opening session he was appointed to consider bills concerned with the conversion of woodland into pasture (28 Apr. 1604) and fen drainage in Cambridgeshire (12 May), always a subject of interest to Lincolnshire Members.
Re-elected for Lincoln in 1614, Grantham’s first appointment was to the conference with the Lords on the Palatine marriage bill (14 April).
James I, en route to Scotland in 1617, visited Lincoln and lodged at Grantham’s house at St. Katherine’s.
Re-elected to the last Jacobean Parliament for Lincolnshire, Grantham’s departure for Westminster was delayed by a dispute between Boston and the county over sluice repairs, which the Privy Council ordered him to investigate.
In the first Parliament of the new reign, Grantham was elected at Lincoln and named to the privileges committee (21 June 1625), and to two legislative committees concerning larceny (25 June) and the limitation of benefit of clergy (25 June).
Re-elected the following year, Grantham was appointed to consider bills to abolish proceedings for concealed tenures (14 Feb. 1626), the holding of secret inquisitions (14 Feb.), and the use of nil returns by escheators (3 May).
Back in his county after the dissolution, Grantham was dismissed from the magistrates’ bench, presumably as a punishment for his zeal against recusants and his attitude to Buckingham; he went on to become one of several Lincolnshire commissioners for the Forced Loan who refused either to collect or lend.
As a schoolboy, the future regicide John Hutchinson† boarded with Grantham at St. Katherine’s during the early 1630s, and it is to him that we owe a description of his host as ‘a gentleman of great repute in his country’, who ‘kept up all his life the old hospitality of England, having a great retinue and a noble table and a resort of all the nobility and gentry in those parts’.
