facet-def.xml

<facets xmlns="http://expath.org/ns/facet">
    <facet-definition name="script" label="Script">
        <group-by function="scriptValues">
            <sub-path>descendant::tei:msDesc/tei:physDesc/tei:handDesc/tei:handNote/@script</sub-path>
        </group-by>
        <max-values show="5">10</max-values>
        <order-by direction="ascending">value</order-by>
    </facet-definition>
    <facet-definition name="material" label="Material">
        <group-by function="materialValues">
            <sub-path>descendant::tei:msDesc/tei:physDesc/tei:objectDesc/tei:supportDesc/@material</sub-path>
        </group-by>
        <max-values show="5">10</max-values>
        <order-by direction="ascending">value</order-by>
    </facet-definition>
    <facet-definition name="classfication" label="Wright's Subject Classification">
        <group-by>
            <sub-path>descendant::tei:msDesc/tei:head/tei:listRelation[@type="Wright-BL-Taxonomy"]/tei:relation[@name="dcterms:type"]/tei:desc</sub-path>
        </group-by>
        <max-values show="5">10</max-values>
        <order-by direction="ascending">value</order-by>
    </facet-definition>
    <!-- 
        /TEI/teiHeader/fileDesc/sourceDesc/msDesc/head/listRelation[@type="Wright-BL-Taxonomy"]/relation[@name="dcterms:type"]
    Here are those xpaths:

Date: /TEI/teiHeader/fileDesc/sourceDesc/msDesc/history/origin/origDate. We will want to use the @notBefore, @notAfter, @from, @to, and @when attributes.
Note that there is sometimes an //origDate element with @notBefore-custom, etc. attributes but we don't want to use these for the slider
    -->
</facets>