Oberlin College canceled classes on Monday and convened a “day of solidarity” instead, after a person wearing a robe and hood appeared near its Afrikan Heritage House early Monday morning, the latest in a string of what it described as hate-related incidents and vandalism in the last month.That event and a number of others are being investigated by the college’s security staff and the Oberlin city police.The sighting of the person on Monday, “in addition to the series of other hate-related incidents on campus, has precipitated our decision to suspend formal classes and all nonessential activities for today, Monday, March 4, 2013, and gather for a series of discussions of the challenging issues that have faced our community in recent weeks,” according to a statement issued by Marvin Krislov, Oberlin’s president, and three college deans.In the last month, a number of racist and antigay messages have been left around campus, a jarring incongruity in a place with the liberal political leanings and traditions of Oberlin, a school of 2,800 students in Ohio, about 30 miles southwest of Cleveland. Guides to colleges routinely list it as among the most liberal, activist and gay-friendly schools in the country.“I’m not sure why anyone is doing it, but those actions have made people uneasy and say we need to come together and discuss this,” said Scott Wargo, an Oberlin spokesman.Founded in 1833, Oberlin was one of the first colleges in the nation to educate women and men together, and one of the first to admit black students. Before the Civil War, it was an abolitionist hotbed and an important stop on the underground railroad.