He was born in 1572, the 2nd son of Henry Mordaunt and Anne Poley. No "Sir" then, that came later, but his family were reasonably wealthy and well connected. His name incidentally came from his grandmother, Barbara L'Estrange, an heiress who bought the manors of Massingham Parva (now Little Massingham) in Norfolk and Walton D'Evile (!), near Wellesbourne in Warwickshire, to the family. Henry and Anne lived in Kings Lynn, but Massingham Parva was destined to be L'Estange's family home.
In Lynn young L'Estrange learnt the customary lessons of the day, writing, French and Latin, but also how to use weapons. Lynn, being an international port, bought frequent news of the outside world. France split between Catholics and Protestants, Holland fighting for it's independence against Spain (based in what we now call Belgium), and further afield stories of the New World, and English raids on the Spanish treasure fleet.
Kings Lynn Guildhall
L'Estrange decided on a military career and for active service joined the English army in Flanders. This was more or less a continuation of the Armada campaign, with English, Dutch and French Portestant troops at one time or another fighting the Spanish or French Catholics.
Late 16th century Guildhouses in Antwerp
L'Estrange had other adventures beyond the war however. Whilst quartered in Antwerp he courted Margaret de Charles, daughter of a "Flemish Gentleman" and exile from the Dutch Republic, Peter de Charles, and he married her and took her back to live in Massingham.
The Mordaunt family had quite an interest in events in Ireland, with a distant cousin, Nicholas Mordaunt, holding a post there. With Ireland being by far the biggest English military commitment, it was natural that L`Estrange would end up there sooner or later.
Since 1595 much of Ireland had been in revolt against English rule, led by the Earl of Tyrone and equipped by the Spanish. The Irish mainly fought with javelin, and increasingly, with musket, and it helped that Tyrone was a much more effective general than most of those he faced, drawing the English troops through boggy ground and into his fire. The English fought with pike and shot, but their strength was their cavalry, semi-armoured and with lances, although Tyrone rarely gave them a chance to charge over open ground. The Irish won battle after battle, culminating in the Battle of Yellow Ford, where 2,000 English troops were killed.
Elizabeth`s response was to raise an army of 16,000 men to crush the rebellion, the largest army England had yet formed, and including young L`Estrange. Unfortunately it was placed under the command of Elizabeth`s favourite, the Earl of Essex. Essex`s strategy of pacifying the south before taking on Tyrone`s forces in the north was not necessarily bad, but was poorly carried out. English troops were split amongst many small garrisons, where many simply died of dysentery, whilst Essex showed no great urgency. When he did attack it was on terrain suited to the Irish forces, such as at the disastrous Battle of Curlew Ridge. Essex was always looking back to court, and in 1599 he deserted Ireland without permission to return to London, and a sticky end.
Lord Mountjoy in 1594
Fortunately for L`Estrange and the other English troops, Essex was succeeded by Lord Mountjoy, experienced of wars on the continent as well as an expedition to the Azores. Mountjoy in turn appointed two men experienced of Irish warfare, George Carew and Arthur Chichester, as his leutenants. Carew had pacified Munster by 1601, whilst with amphibious landings at Londonderry and Carrickfergus Chichester invaded Ulster. A Spanish force of 4,000 soldiers landed at Cork with the aim of sandwiching the English between them and Tyrone's forces marching south, but in January 1602 Mountjoy managed to catch the Irish forces on open ground. For once fighting on their own terms, the English cavalry destroyed the Irish foot, and the rebellion was effectively over.
L`Estrange returned to England, doubtless with considerable relief. Thousands of English troops had died from hunger or disease, many more than enemy action, and it had not been a glorious war. None the less he had emerged with credit, and enhanced his reputation in high circles.
With the effective end of the war in early 1602 L`Estrange returned home, and in May the death of his uncle Robert left him a wealthy man at 30 years old. Sadly in 1606 his Flemish wife Margaret died and was laid to rest in Little Massingham church. L`Estrange married Frances Sotherton, a widow from Norwich, in 1608.
Little Massingham church
The transition from Elizabeth to James I seems to have made little difference to L`Estrange's fortunes, but the Gunpowder Plot did draw in members of his family. Lord Mordaunt, a relative, was suspected of involvement and fined 10,000 pounds. However, to balance this Sir Gilbert Pickering was one of those most active investigators of the plot, and Sir Gilbert's son later married L`Estrange's grand daughter, so maybe there was some useful connection at the time.
L'Estrange propsered and in 1606-7 he was Sheriff of Norfolk. Certainly in 1611 L`Estrange was in favour at court, or rather his money was.
James I needed cash and he came up with the bright idea of selling "Baronetcies", a new form of nobleman. The plan was "offered" to 200 men of good breeding, all they had to do was stump up money equivalent for 3 years pay for 30 soldiers, which came out at £1,095 - a days pay was reckoned to be 8 pence. How much of that money actually went to the army, who were notoriously badly paid, is unknown, but any way on 29th of June 1611, L'Estrange Mordaunt became Baron Mordaunt of Massingham Parva.
Baron Mordaunt lived to see his son Robert knighted by James 1 in 1620, but he died aged 55 in 1627, and was buried next to his first wife in Little Massingham Church.
Much of the above comes from Massingham Parva Past and Present, (1882), by Robert Fisher McLeod available online at archive.org