Before he ever sat in the captain's chair, Patrick Stewart spent sixteen years with the Royal Shakespeare Company, from 1966 to 1982, and picked up screen work around the edges. Then Star Trek: The Next Generation producer Robert H. Justman saw him at a literary reading at UCLA, and in 1987 the rest of the world met him as Jean-Luc Picard.
British viewers had met him already. Through the 1970s and early 1980s he played a Roman schemer, a Russian revolutionary, a Soviet spymaster, an Arthurian king and a Tudor duke. Most of it survives, and most of it is easy to find.
The Picard to come is hiding in the BBC serials. The films gave him costumes and a few scenes. Television gave him rooms full of powerful people and the time to dominate them by thinking. Best first:








The films mostly used him as authority in a costume, and Lifeforce eventually hands him over to the special effects team. The serials let him build a man across whole episodes. Sejanus and Lenin are opposites, a man who wants power for himself and a man who wants it for an idea, and Picard sits between them: a commander who can be ruthless and still believes in the argument. Watching them back to back, it is easy to see why Justman, sitting in that UCLA audience, did not need to see much more.
The Plague Dogs (1982) is an animated Richard Adams adaptation in which John Hurt voices the terrier Snitter and Stewart voices John Awdry. It is beautiful and harrowing, so think twice before showing it to children. In Hennessy (1975) he plays Tilney in Rod Steiger's thriller about a man plotting to blow up the Houses of Parliament. And Wild Geese II (1985) gives him a small role as a Russian general, a job Wikipedia reports he took mostly to pay for home repairs and later called the biggest embarrassment of his career. Seeing it once is enough.
Put on episode 5 of I, Claudius and watch Sejanus arrive. If you only have two hours, watch Dune instead and keep an eye on Gurney. Then save the Lenin episodes of Fall of Eagles for a quiet evening, because that is where you can see the captain coming, thirteen years before anyone gave him a ship.