Francis, Lord of Someldeyck and Spycyk, was one of the greatest ministers for negotiation the United Provinces could ever boast of. His father, Cornelius Aarssens, was registrar to the States; and being acquainted with Mr Pleiss Mornay, at the court of William prince of Orange, he prevailed upon him to take his son under him, with whom he continued some years. John Olden Barneveldt, who presided over the affairs of Holland and all the United Provinces, sent him afterwards agent into France, where he learned to negotiate under those profound politicians Henry IV. Villeroy, Silleri, Rossie, Jaonnin, &c., and he acquitted himself in such a manner as to obtain their approbation. Soon after, he was invested with the character of ambassador, and was the first who was recognized as such by the French court; at which time Henry IV. declared, that he should take precedence next to the Venetian minister. He resided in France 15 years; during which time he received great marks of esteem from the king, who created him a knight and baron; and for this reason he was received among the nobles of the province of Holland. However, he became at length so odious to the French court, that they desired to have him recalled. He was afterwards deputed to Venice, and to several German and Italian princes, upon occasion of the troubles in Bohemia. He was the first of three extraordinary ambassadors sent to England in 1620, and the second in 1641; in which latter embassy he was accompanied by the lord of Brederode as first ambassador, and Heemvliet as third, to negotiate the marriage of Prince William, son of the prince of Orange, with a daughter. daughter of Charles I. He was likewise ambassador extraordinary at the French court in 1624, at the beginning of Cardinal Richelieu's administration, who had a high opinion of him. The memoirs which he has left, of the negotiations in which he was engaged, show him to have been one of the ablest men of his time, and worthy of the confidence and trust reposed in him by his country. But his character is not altogether without flaw. His enmity to the remonstrants was bitter and unrelenting; and he is supposed to have greatly encouraged the violent measures pursued by Prince Maurice against the venerable Barneveldt, and to have been the principal adviser for assembling the famous and persecuting synod of Dordrecht. He died at a very advanced age; and his son, who survived him, was reputed the wealthiest man in Holland.