The initials are of Philo Laos Mills of Mills and Gibb, Lace Makers. At its peak in 1914 there were 1548 warehouses and manufactures in the Lace Market but by the time of this photograph, the lace and textile industry had seriously declined. Many buildings were let out and little spent on their maintenance and some buildings demolished. (The area is now recovering as many of the lace warehouses have been converted to apartments and is thriving with cafes and bars).