Leonardo of Veruli (Italian

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

 Leonardo da Veroli) was the chancellor

Chancellor

Chancellor is the title of various official positions in the governments of many nations. The original chancellors were the Cancellarii of Roman courts of justice—ushers who sat at the cancelli or lattice work screens of a basilica or law court, which separated the judge and counsel from the...

 to and close adviser of William II Villehardouin, Prince of Achaea.

In 1239, Leonardo married Marguerite, the daughter of Narjot de Toucy

Narjot de Toucy (died 1241)

Narjot de Toucy , lord of Bazarnes, was the son of Narjot II of Toucy and of his wife Agnes de Dampierre.Alongside his father-in-law Theodore Branas and Geoffroy de Merry, Narjot de Toucy formed part of the council that briefly governed Constantinople from 17 December 1219 Narjot de Toucy (died...

, then regent

Regent

A regent, from the Latin regens "one who reigns", is a person selected to act as head of state because the ruler is a minor, not present, or debilitated. Currently there are only two ruling Regencies in the world, sovereign Liechtenstein and the Malaysian constitutive state of Terengganu...

 of the Latin Empire

Latin Empire

The Latin Empire or Latin Empire of Constantinople is the name given by historians to the feudal Crusader state founded by the leaders of the Fourth Crusade on lands captured from the Byzantine Empire. It was established after the capture of Constantinople in 1204 and lasted until 1261...

.

In 1267, he ratified the Treaty of Viterbo

Treaty of Viterbo

The Treaty of Viterbo was a pair of agreements made by Charles I of Sicily with Baldwin II of Constantinople and William II Villehardouin, Prince of Achaea, on 27 May 1267, which transferred much of the rights to the Latin Empire from Baldwin to Charles.-Background:The recapture of Constantinople...

 on behalf of William, sealing a marital pact between Philip, the son of Charles I of Sicily

Charles I of Sicily

Charles I , known also as Charles of Anjou, was the King of Sicily by conquest from 1266, though he had received it as a papal grant in 1262 and was expelled from the island in the aftermath of the Sicilian Vespers of 1282...

 and William's daughter Isabella of Villehardouin

Isabella of Villehardouin

Isabella of Villehardouin was the elder daughter of William II of Villehardouin, Prince of Achaea, and of his second wife Anna, the third daughter of Michael II Komnenos Doukas, the despot of Epiros....

 and providing for the transfer of the Principality to the Angevins

Capetian House of Anjou

The Capetian House of Anjou, also known as the House of Anjou-Sicily and House of Anjou-Naples, was a royal house and cadet branch of the direct House of Capet. Founded by Charles I of Sicily, a son of Louis VIII of France, the Capetian king first ruled the Kingdom of Sicily during the 13th century...

.