The right of sub-infeudation granted to the recipients of the land grants caused the depression of the peasantry primarily because it reduced the permanent tenants to the position of tenants-at-will. Let's delve deeper into this issue:

1. Sub-infeudation and its impact:
- Sub-infeudation was a practice in medieval Europe where the primary landowner granted a portion of their land to another person, who in turn became a sub-tenant.
- This sub-tenant could then grant a portion of the land to another person, creating a chain of sub-tenants.
- As the practice continued, the original landowner became the overlord of all the sub-tenants in the hierarchy.

2. Reduction to tenants-at-will:
- The right of sub-infeudation led to a significant reduction in the status and security of the permanent tenants.
- Previously, these tenants held their lands as permanent tenants, giving them some stability and security.
- However, with the introduction of sub-infeudation, these tenants were reduced to tenants-at-will, meaning they could be evicted or have their rents increased at the whim of the sub-tenant or the overlord.
- This weakened their position and made them vulnerable to exploitation and abuse.

3. Dependence on vassals:
- The sub-tenants who were granted land through sub-infeudation became the vassals of the overlord.
- The permanent tenants were now at the mercy of these vassals, who often held significant power and authority.
- The vassals could demand higher rents, impose additional obligations, or even evict the tenants to make room for their own supporters or family members.
- This further exacerbated the depression of the peasantry as they became subject to the whims and interests of the vassals.

4. Reduced share of produce:
- Another consequence of sub-infeudation was the reduction in the share of produce that the peasantry received.
- As the chain of sub-tenants grew, the produce from the land had to be shared among a larger number of people.
- This resulted in a decrease in the portion of produce that each tenant received, further worsening their economic situation.

In conclusion, the right of sub-infeudation granted to the recipients of land grants caused the depression of the peasantry primarily by reducing the permanent tenants to the position of tenants-at-will. This diminished their security, made them dependent on vassals, and reduced their share of the produce. These factors collectively contributed to the economic and social hardships faced by the peasantry during this period.