[url]http://www.nytimes.com/2002/05/12/national/12PHIL.html[/url/]

The First City Troop, the clubby social wing of a 200-year-old cavalry unit, usually provides ceremonial escorts for presidents, promotes horsemanship and holds galas in the suburbs.

This month, it will begin training for a peacekeeping mission in Bosnia — its first call-up in 50 years.

"The first reaction was, `Is this a joke?' Now I think people are adjusting," said Eric Guenther Jr., 39, a pharmaceutical executive who is commander of the National Guard unit.

Many of its 70 active-duty members, including bankers, lawyers and business executives, will train at the Army's Fort Indiantown Gap before being sent to Germany in August. They will go to Bosnia in October.

The call-up will test members trying to balance their patriotism with big mortgages and private school tuition bills. About half could decide not to go because their current National Guard contracts end before March 2003, when the unit is expected to return home.

"Some of the guys are struggling quite a bit, trying to come up with the right decision," said Mr. Guenther, who has to leave behind his wife and two young daughters

"We obviously have a number of people who make over six figures," he added.

On active duty, they will make $25,000 to $55,000 a year. Over the last two centuries, troop members have included the sons of many of Philadelphia's most prominent families.

Three volunteers organized the troop, originally called the Philadelphia Light Horse, in Carpenters Hall in November 1774 to defend the colonies.

The group, which now has members who have served in Vietnam, Grenada and Desert Storm, is the oldest mounted unit in the country in continuous service, although cavalry units now serve on tanks and Humvees, not on horseback.

By tradition, troop members donate their guard pay to support social activities and the upkeep of artifacts housed at the unit's castlelike armory in Philadelphia.

The First City Troop has about 700 members, most of them retired from the guard. New members are welcome, Mr. Guenther said. "The troop is sort of the last of the breed because we've changed with the times," he said.