The story of the massacre of York's medieval Jewish community and much more will be easily accessible to tourists for the first time, thanks to the work of historian Professor Helen Weinstein.

Prof Weinstein, director of York University's Institute for the Public Understanding of the Past, has helped bring to fruition a downloadable app that takes visitors on a journey through the city's Jewish heritage.

The free app, which will be available for Apple and Android devices, features a map that will alert visitors to nearby points of interest, and provide audio commentary, old photographs and other information when they get there.

Chief among these is Clifford's Tower, which on March 16 1190 was the site of a massacre of an estimated 150 Jews - most of the community. They fled there to escape a murderous mob, believed to be incited by the coronation of crusader King Richard I. The rioters laid siege to the tower and for several days the Jews were trapped inside, before the tower was set alight. Accounts vary, but it is thought that some died from fire and others chose to commit suicide. The tower was destroyed but was rebuilt with money from a fine levied on the city because of the massacre. Today, a candlelight vigil is held there on Holocaust Memorial Day to commemorate the victims.

But Prof Weinstein wants to educate visitors to the fact that there is more to York's Jewish past than tragedy. "I wanted to reclaim the city where Jews lived and worshipped and look at what trace is left of that community," she said.

The app directs people to six other sites, showing that Jews in York were not ghettoised as others were in medieval Europe. "York's Jewish past is a really important part of the history of the city but at the moment if you go to the York Tourist Office there is nothing available to help you understand it," said Prof Weinstein. "When I arrived in York, I was shocked, as a Jew, that there was nothing to tell this story."

The app will be launched on the anniversary of the massacre via the History of York website.