====== 661 Time Period ======
\\
^Mandatory ^Repeatable ^Editable |
|no|may only occur once per ownership description|yes|

===== Scope =====
Indicates a geographic area associated with a specific ownership.

===== Indicators =====
  * Indicator 1: **#** undefined (blank)
  * Indicator 2: **#** undefined (blank)

===== Subfields =====
  * **$6** (M;NR) Evidence Sequence Indicator
  * **$a** (M;NR) Time Period Code
  * **$z** (O;NR) Note


===== Input Conventions =====
The evidence sequence indicator in **$6** groups all chunks of information that describe the evidence for a specific ownership. All fields with an identical subfield $6 within a record describe the same ownership.

Subfield **$a** consists of 4 code positions:
|c/p0|Start of time period - century|
|c/p1|Start of time period - decade|
|c/p2|End of time period - century|
|c/p3|End of time period - decade|

The following codes are used:

^Century^^Decade||
|s|15th|0|1st|
|t|16th|1|2nd|
|u|17th|2|3rd|
|v|18th|3|4th|
|w|19th|4|5th|
|x|20th|5|6th|
|y|21st|6|7th|
|-|unknown|7|8th|
|  ||8|9th|
|  ||9|10th|
|  ||-|unknown|