With The Forgotten Kingdom, multi-instrumentalist/composer Guy Mendilow assembled a touring show from the half-lost music of Sephardic Jews from the Balkans. Working with traditional songs sung in Ladino, the Spanish-rooted language of the Sephardim, Mendilow recast them into forms that respect the past and are comfortable in the present. The powerfully emotive voice of Sofia Tosello is the through-line connecting songs whose moody arrangements include guitar and electric bass along with traditional Levantine string instruments. She would sound good in duet with Dead Can Dance’s Lisa Gerrard.