John IV Palaeologus (June 24, 1413 – January 19, 1464) was the Margrave of Montferrat from 1445 until his death.

The eldest of four brothers and two sisters, he was born near Casale

Casale Monferrato

Casale Monferrato, population 36,058, is a town and comune in the Piedmont region of north-west Italy, part of the province of Alessandria. It is situated about 60 km east of Turin on the right bank of the Po, where the river runs at the foot of the Montferrato hills. Beyond the river lies the...

 in the castle of Pontestura

Pontestura

Pontestura is a commune with a population of 1,539 in the Province of Alessandria in the Italian region Piedmont...

, to John Jacob of Montferrat

John Jacob of Montferrat

John Jacob Palaeologus was the Margrave of Montferrat from 1418 to 1435....

 and Joan of Savoy, daughter of Amadeus VII (the Red Count of Savoy). During his father’s unlucky war against Amadeus VIII of Savoy, he was imprisoned by the latter and used as hostage.

He fought as condottiere for the Republic of Venice

Republic of Venice

The Republic of Venice or Venetian Republic was a state originating from the city of Venice in Northeastern Italy. It existed for over a millennium, from the late 7th century until 1797. It was formally known as the Most Serene Republic of Venice and is often referred to as La Serenissima, in...

 in the war that ensued after the heirless death of Filippo Maria Visconti

Filippo Maria Visconti

Filippo Maria Visconti was ruler of Milan from 1412 to 1447.-Biography:Filippo Maria Visconti, who had become nominal ruler of Pavia in 1402, succeeded his assassinated brother Gian Maria Visconti as Duke of Milan in 1412. They were the sons of Gian Galeazzo Visconti, Gian Maria's predecessor, by...

 of Milan

Milan

Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...

 (see Wars in Lombardy

Wars in Lombardy

The wars in Lombardy were a series of conflicts fought in central-northern Italy between the Republic of Venice and the Duchy of Milan, and their different allies. They lasted from 1425 until the signing of the Treaty of Lodi in 1454...

). During his reign the Palaeologus family lost the throne of Constantinople

Constantinople

Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

, captured by the Ottoman Turks in 1453.

He set his mind rather belatedly to ensuring future of the dynasty, marrying Margherita, daughter of Louis of Savoy and Anne of Cyprus

Anne of Cyprus

Anne of Cyprus was the daughter of King Janus of Cyprus and Charlotte de Bourbon; and a member of the celebrated Lusignan crusader dynasty...

, in Casale in December 1458. She brought a dowry of 100,000 scudi, receiving Trino

Trino

Trino is a comune in the Province of Vercelli in the Italian region Piedmont, located about 50 km northeast of Turin and about 15 km southwest of Vercelli, at the foot of the Montferrat hills....

, Morano

Morano sul Po

Morano sul Po is a comune with a population of 1,587 and an area of 17.7 km² in the Province of Alessandria in the Italian region Piedmont....

, Borgo San Martino

Borgo San Martino

Borgo San Martino is a comune in the Province of Alessandria in the Italian region Piedmont, located about 60 km east of Turin and about 20 km northwest of Alessandria....

 and Mombaruzzo

Mombaruzzo

Mombaruzzo is a comune in the Province of Asti in the Italian region Piedmont, located about 70 km southeast of Turin and about 25 km southeast of Asti....

 in return. However they had no children.

John IV died, without legitimate heirs, in Casale on 19 January 1464; he was buried there alongside his father in the church of San Francesco. He was succeeded by his brother William VIII.