Until some time in the 18th century, the trombone was in A and the pitch of that A was about a half-step higher than it is today—460–480 Hz. There was a transition around the 18th century when trombones started to be thought of in B at around 440 Hz. This change did not require a change in the instrument, merely a new set of slide positions for each note. But it does mean that the baroque and renaissance repertoire was intended to be played at the higher pitch. There are many examples of evidence for this: