New York Mayor Michael Bloomberg has thanked the four New York state GOP senators who voted for gay marriage by donating the maximum to their reelection campaigns.

Bloomberg, a Republican turned independent, made out checks of $10,300 – the maximum allowed – to Republican Senators Mark Grisanti of Buffalo, James Alesi of Rochester, Roy McDonald of Saratoga and Stephen Saland of Poughkeepsie.

The mayor had lobbied for passage of the law. He delivered a major speech calling on lawmakers to approve marriage equality and traveled twice to Albany to meet with undecided lawmakers.

“The mayor said he would support Senate Republicans who stood up – and he did,” Micah Lasher, a Bloomberg staffer, told The New York Daily News.

(Related: Michael Bloomberg to officiate over the same-sex wedding of two of his top staffers.)

Grisanti, considered the most vulnerable of the four Republicans, received another $40,000 in donations from people who publicly back gay marriage rights, including $10,000 from gay philanthropist Tim Gill.

“I didn't vote that way to get campaign contributions,” the Buffalo News quoted Grisanti as saying.

Gay marriage foes have labeled Grisanti a traitor for his vote and have vowed to work against his reelection. The Buffalo-area lawyer turned lawmaker said he was “inalterably” opposed to marriage equality during a failed 2008 campaign bid.

On the Senate floor before he cast his vote that helped New York become the sixth – and most populous – state to legalize gay marriage, Grisanti told lawmakers that he could not find a legal reason to oppose marriage equality.