since 

identifies the reference point for determining the time of the current
when element, which is obtained by adding the interval to the time of the reference
point.

Attribute Information

Used By

Element tei:when

Source 

<xs:attribute name="since" type="xs:anyURI">
  <xs:annotation>
    <xs:documentation>identifies the reference point for determining the time of the current when element, which is obtained by adding the interval to the time of the reference point.</xs:documentation>
  </xs:annotation>
</xs:attribute>

Sample