In which meter were shakespearean sonnets written?

Different languages have different metres as their natural Sonnet line.

In English, by far the commonest metre for a sonnet is Iambic Pentameter:

For whom the possessed sea littered, on both shores,

Ruinous arms; being fired, and for good,

But Iambic Tetrameter is also found:

My shrink said "lucid dreaming" tames

recurring nightmares. What the bleep -

And occasionally you will come across even more exotic metres.