Original: The Victoria line was designed to relieve congestion on other lines, in particular the Piccadilly line, as well as to maximize possible interchanges.
Simplified: The Victoria line was designed to get rid of build-ups of traffic on other lines, such as the Piccadilly line. It was also designed to have as many interchanges as possible, and all stations except Pimlico have an interchange with at least one other London Underground or National Rail line.