Henceforth each of these schools was to be managed by a board of governors. The following year, the headmaster of Uppingham School invited sixty to seventy of his fellow headmasters to form what became the Headmasters' Conference – later the Headmasters' and Headmistresses' Conference. Separate preparatory (or "prep") schools developed from the 1830s, which "prepared" younger boys for entry to the senior schools; as a result the latter began limiting entry to boys who had reached 12 or 13 years of age.