Well, as is told in Marco Polo’s Travels, Nicolo, Marco’s father, had a wife—I do not believe she is named— whom he left with child before departing for a considerable time—around 18-20 years. She passed away in this time, but his son, our young Master Marco, was alive, presumably staying with other relatives and, when he was in his older teens, taking up the care of the family home himself. It was decided by Nicolo and his brother to bring Marco back with them to the grand khan when they returned to him, since they were serving as ambassadors to the pope for him.

You’re right in thinking that letters would not be sent back; even within the Mongolian Empire there were problems with connectivity, since it was so large, the distances travelled might take years for a given party of individuals, and some sections were impossible with groups that were too large—due to lack of resources—or too small—due to a lack of proper policing. The Polos would certainly have travelled in moderately sized groups, maybe 50-200 people, perhaps more, when they were journeying on the khan’s business. One journey made in the service of the Kubilai, sometime around 1295, is the last that Marco made, and the group is listed at 600 individuals. So, letters would certainly not be sent home, and we have to consider some other way of knowing how their property was protected.

We also can see from the Travels a real preoccupation with the rulers of the individual nations; for example, the Polos are eager to leave Kubilai’s court before he dies, since their stay there is wholly dependent on him, and should he die all their opportunity at mobility, or even life, would be lost. Therefore, we can guess with some certainty that the sovereigns would be protective of the Polos, or anyone like them, who happens to be in their service, since their skills, and indeed their sacrifices, are essential to the workings of international diplomacy. Around this time we have many other travelers, all of whom are enabled to do so because of their service as both ambassadors and courtiers in the respective courts they may find themselves in. Ibn Battuta and Rabban Sauma are two individuals who come to mind, serving similar roles in courts throughout the world during the 13th and 14th centuries.

In the Polos’ case, I think it is fair to say that their relatives would have protected their property as much as they could, that they would have had their services both to the papacy and Kubilai known to the doge of Venice for its protection, or that they would have sold much of their possessions before departing, since they knew full well that they would not be returning anytime soon. Other traveling ambassadors and courtiers—Ibn Battuta is the one I know best—are honored by their homeland when they return home as wizened and learned individuals, and are known throughout the community. Presumably this would be because of the actions of their friends or relatives. Marco, however, finds himself in prison in Genoa just a short while after returning home, since he had used his fortunes acquired in the east to equip a ship to fight in the war against that city. When he was released sometime around 1299-1300, he found that his father and uncle had bought a large home with their acquisitions from the east, plus more garnered from financing trading excursions.

If I had to make my own educated guess, I would say the Polos relied more on friends and relatives to protect their property for them; there seems to be some sort of disconnect between Marco and the government later in life, which I personally know little about, but besides this we do not see the loving attitude that other writers hold for their homeland; whereas Ibn Battuta enumerates a loving description of the sovereign of his homeland, Marco praises God that he has returned and paints no grand picture of Venice itself, and indeed you can sense a tone of sadness in the Travels when it is related that he cannot return to the east after Kubilai’s death.