〜たまえ

たまえ is a command used by men speaking to someone of lower status, such as a boss to a subordinate or a professor to a student: 遠慮せずに、座りたまえ, "don't be shy, have a seat".

It attaches to the ます-stem: 座り + たまえ, 飲み + たまえ, 考え + たまえ. It sounds authoritative but not rude, a bit old-fashioned, and very common for company presidents, teachers and aristocrats in fiction.

It comes from the classical honorific 給う ("to bestow"), so it was originally respectful. Today it's the opposite: only a superior uses it.

In everyday speech, you'd use なさい (N4) or てください.