In the 19th century, the acciaccatura (sometimes called "short appoggiatura") came to be a shorter variant of the "long appoggiatura", where the delay of the principal note is quick. It is written using a grace note (often a quaver, or eighth note), with an oblique stroke through the stem. In the Classical period, an acciaccatura is usually performed before the beat and the emphasis is on the main note, not the grace note. The "appoggiatura" long or short has the emphasis on the grace note.